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20150812-1 选题 RHCE 专题 文章未全部完结，目前只有三篇
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Part 1 - RHCE Series: How to Setup and Test Static Network Routing
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================================================================================
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RHCE (Red Hat Certified Engineer) is a certification from Red Hat company, which gives an open source operating system and software to the enterprise community, It also gives training, support and consulting services for the companies.
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RHCE Exam Preparation Guide
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This RHCE (Red Hat Certified Engineer) is a performance-based exam (codename EX300), who possesses the additional skills, knowledge, and abilities required of a senior system administrator responsible for Red Hat Enterprise Linux (RHEL) systems.
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**Important**: [Red Hat Certified System Administrator][1] (RHCSA) certification is required to earn RHCE certification.
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Following are the exam objectives based on the Red Hat Enterprise Linux 7 version of the exam, which will going to cover in this RHCE series:
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- Part 1: How to Setup and Test Static Routing in RHEL 7
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- Part 2: How to Perform Packet Filtering, Network Address Translation and Set Kernel Runtime Parameters
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- Part 3: How to Produce and Deliver System Activity Reports Using Linux Toolsets
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- Part 4: Automate System Maintenance Tasks Using Shell Scripts
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- Part 5: How to Configure Local and Remote System Logging
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- Part 6: How to Configure a Samba Server and a NFS Server
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- Part 7: Setting Up Complete SMTP Server for Mailing
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- Part 8: Setting Up HTTPS and TLS on RHEL 7
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- Part 9: Setting Up Network Time Protocol
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- Part 10: How to Configure a Cache-Only DNS Server
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To view fees and register for an exam in your country, check the [RHCE Certification][2] page.
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In this Part 1 of the RHCE series and the next, we will present basic, yet typical, cases where the principles of static routing, packet filtering, and network address translation come into play.
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RHCE: Setup and Test Network Static Routing – Part 1
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Please note that we will not cover them in depth, but rather organize these contents in such a way that will be helpful to take the first steps and build from there.
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### Static Routing in Red Hat Enterprise Linux 7 ###
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One of the wonders of modern networking is the vast availability of devices that can connect groups of computers, whether in relatively small numbers and confined to a single room or several machines in the same building, city, country, or across continents.
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However, in order to effectively accomplish this in any situation, network packets need to be routed, or in other words, the path they follow from source to destination must be ruled somehow.
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Static routing is the process of specifying a route for network packets other than the default, which is provided by a network device known as the default gateway. Unless specified otherwise through static routing, network packets are directed to the default gateway; with static routing, other paths are defined based on predefined criteria, such as the packet destination.
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Let us define the following scenario for this tutorial. We have a Red Hat Enterprise Linux 7 box connecting to router #1 [192.168.0.1] to access the Internet and machines in 192.168.0.0/24.
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A second router (router #2) has two network interface cards: enp0s3 is also connected to router #1 to access the Internet and to communicate with the RHEL 7 box and other machines in the same network, whereas the other (enp0s8) is used to grant access to the 10.0.0.0/24 network where internal services reside, such as a web and / or database server.
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This scenario is illustrated in the diagram below:
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Static Routing Network Diagram
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In this article we will focus exclusively on setting up the routing table on our RHEL 7 box to make sure that it can both access the Internet through router #1 and the internal network via router #2.
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In RHEL 7, you will use the [ip command][3] to configure and show devices and routing using the command line. These changes can take effect immediately on a running system but since they are not persistent across reboots, we will use ifcfg-enp0sX and route-enp0sX files inside /etc/sysconfig/network-scripts to save our configuration permanently.
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To begin, let’s print our current routing table:
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# ip route show
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Check Current Routing Table
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From the output above, we can see the following facts:
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- The default gateway’s IP address is 192.168.0.1 and can be accessed via the enp0s3 NIC.
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- When the system booted up, it enabled the zeroconf route to 169.254.0.0/16 (just in case). In few words, if a machine is set to obtain an IP address through DHCP but fails to do so for some reason, it is automatically assigned an address in this network. Bottom line is, this route will allow us to communicate, also via enp0s3, with other machines who have failed to obtain an IP address from a DHCP server.
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- Last, but not least, we can communicate with other boxes inside the 192.168.0.0/24 network through enp0s3, whose IP address is 192.168.0.18.
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These are the typical tasks that you would have to perform in such a setting. Unless specified otherwise, the following tasks should be performed in router #2:
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Make sure all NICs have been properly installed:
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# ip link show
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If one of them is down, bring it up:
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# ip link set dev enp0s8 up
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and assign an IP address in the 10.0.0.0/24 network to it:
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# ip addr add 10.0.0.17 dev enp0s8
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Oops! We made a mistake in the IP address. We will have to remove the one we assigned earlier and then add the right one (10.0.0.18):
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# ip addr del 10.0.0.17 dev enp0s8
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# ip addr add 10.0.0.18 dev enp0s8
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Now, please note that you can only add a route to a destination network through a gateway that is itself already reachable. For that reason, we need to assign an IP address within the 192.168.0.0/24 range to enp0s3 so that our RHEL 7 box can communicate with it:
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# ip addr add 192.168.0.19 dev enp0s3
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Finally, we will need to enable packet forwarding:
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# echo "1" > /proc/sys/net/ipv4/ip_forward
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and stop / disable (just for the time being – until we cover packet filtering in the next article) the firewall:
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# systemctl stop firewalld
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# systemctl disable firewalld
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Back in our RHEL 7 box (192.168.0.18), let’s configure a route to 10.0.0.0/24 through 192.168.0.19 (enp0s3 in router #2):
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# ip route add 10.0.0.0/24 via 192.168.0.19
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After that, the routing table looks as follows:
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# ip route show
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Confirm Network Routing Table
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Likewise, add the corresponding route in the machine(s) you’re trying to reach in 10.0.0.0/24:
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# ip route add 192.168.0.0/24 via 10.0.0.18
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You can test for basic connectivity using ping:
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In the RHEL 7 box, run
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# ping -c 4 10.0.0.20
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where 10.0.0.20 is the IP address of a web server in the 10.0.0.0/24 network.
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In the web server (10.0.0.20), run
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# ping -c 192.168.0.18
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where 192.168.0.18 is, as you will recall, the IP address of our RHEL 7 machine.
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Alternatively, we can use [tcpdump][4] (you may need to install it with yum install tcpdump) to check the 2-way communication over TCP between our RHEL 7 box and the web server at 10.0.0.20.
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To do so, let’s start the logging in the first machine with:
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# tcpdump -qnnvvv -i enp0s3 host 10.0.0.20
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and from another terminal in the same system let’s telnet to port 80 in the web server (assuming Apache is listening on that port; otherwise, indicate the right port in the following command):
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# telnet 10.0.0.20 80
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The tcpdump log should look as follows:
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Check Network Communication between Servers
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Where the connection has been properly initialized, as we can tell by looking at the 2-way communication between our RHEL 7 box (192.168.0.18) and the web server (10.0.0.20).
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Please remember that these changes will go away when you restart the system. If you want to make them persistent, you will need to edit (or create, if they don’t already exist) the following files, in the same systems where we performed the above commands.
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Though not strictly necessary for our test case, you should know that /etc/sysconfig/network contains system-wide network parameters. A typical /etc/sysconfig/network looks as follows:
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# Enable networking on this system?
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NETWORKING=yes
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# Hostname. Should match the value in /etc/hostname
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HOSTNAME=yourhostnamehere
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# Default gateway
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GATEWAY=XXX.XXX.XXX.XXX
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# Device used to connect to default gateway. Replace X with the appropriate number.
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GATEWAYDEV=enp0sX
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When it comes to setting specific variables and values for each NIC (as we did for router #2), you will have to edit /etc/sysconfig/network-scripts/ifcfg-enp0s3 and /etc/sysconfig/network-scripts/ifcfg-enp0s8.
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Following our case,
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TYPE=Ethernet
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BOOTPROTO=static
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IPADDR=192.168.0.19
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NETMASK=255.255.255.0
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GATEWAY=192.168.0.1
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NAME=enp0s3
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ONBOOT=yes
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and
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TYPE=Ethernet
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BOOTPROTO=static
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IPADDR=10.0.0.18
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NETMASK=255.255.255.0
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GATEWAY=10.0.0.1
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NAME=enp0s8
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ONBOOT=yes
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for enp0s3 and enp0s8, respectively.
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As for routing in our client machine (192.168.0.18), we will need to edit /etc/sysconfig/network-scripts/route-enp0s3:
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10.0.0.0/24 via 192.168.0.19 dev enp0s3
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Now reboot your system and you should see that route in your table.
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### Summary ###
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In this article we have covered the essentials of static routing in Red Hat Enterprise Linux 7. Although scenarios may vary, the case presented here illustrates the required principles and the procedures to perform this task. Before wrapping up, I would like to suggest you to take a look at [Chapter 4][5] of the Securing and Optimizing Linux section in The Linux Documentation Project site for further details on the topics covered here.
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Free ebook on Securing & Optimizing Linux: The Hacking Solution (v.3.0) – This 800+ eBook contains comprehensive collection of Linux security tips and how to use them safely and easily to configure Linux-based applications and services.
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Linux Security and Optimization Book
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[Download Now][6]
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In the next article we will talk about packet filtering and network address translation to sum up the networking basic skills needed for the RHCE certification.
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As always, we look forward to hearing from you, so feel free to leave your questions, comments, and suggestions using the form below.
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--------------------------------------------------------------------------------
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via: http://www.tecmint.com/how-to-setup-and-configure-static-network-routing-in-rhel/
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作者：[Gabriel Cánepa][a]
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译者：[译者ID](https://github.com/译者ID)
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校对：[校对者ID](https://github.com/校对者ID)
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本文由 [LCTT](https://github.com/LCTT/TranslateProject) 原创翻译，[Linux中国](https://linux.cn/) 荣誉推出
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[a]:http://www.tecmint.com/author/gacanepa/
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[1]:http://www.tecmint.com/rhcsa-exam-reviewing-essential-commands-system-documentation/
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[2]:https://www.redhat.com/en/services/certification/rhce
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[3]:http://www.tecmint.com/ip-command-examples/
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[4]:http://www.tecmint.com/12-tcpdump-commands-a-network-sniffer-tool/
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[5]:http://www.tldp.org/LDP/solrhe/Securing-Optimizing-Linux-RH-Edition-v1.3/net-manage.html
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[6]:http://tecmint.tradepub.com/free/w_opeb01/prgm.cgi
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@ -0,0 +1,177 @@
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Part 2 - How to Perform Packet Filtering, Network Address Translation and Set Kernel Runtime Parameters
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================================================================================
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As promised in Part 1 (“[Setup Static Network Routing][1]”), in this article (Part 2 of RHCE series) we will begin by introducing the principles of packet filtering and network address translation (NAT) in Red Hat Enterprise Linux 7, before diving into setting runtime kernel parameters to modify the behavior of a running kernel if certain conditions change or needs arise.
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RHCE: Network Packet Filtering – Part 2
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### Network Packet Filtering in RHEL 7 ###
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When we talk about packet filtering, we refer to a process performed by a firewall in which it reads the header of each data packet that attempts to pass through it. Then, it filters the packet by taking the required action based on rules that have been previously defined by the system administrator.
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As you probably know, beginning with RHEL 7, the default service that manages firewall rules is [firewalld][2]. Like iptables, it talks to the netfilter module in the Linux kernel in order to examine and manipulate network packets. Unlike iptables, updates can take effect immediately without interrupting active connections – you don’t even have to restart the service.
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Another advantage of firewalld is that it allows us to define rules based on pre-configured service names (more on that in a minute).
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In Part 1, we used the following scenario:
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Static Routing Network Diagram
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However, you will recall that we disabled the firewall on router #2 to simplify the example since we had not covered packet filtering yet. Let’s see now how we can enable incoming packets destined for a specific service or port in the destination.
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First, let’s add a permanent rule to allow inbound traffic in enp0s3 (192.168.0.19) to enp0s8 (10.0.0.18):
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# firewall-cmd --permanent --direct --add-rule ipv4 filter FORWARD 0 -i enp0s3 -o enp0s8 -j ACCEPT
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The above command will save the rule to /etc/firewalld/direct.xml:
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# cat /etc/firewalld/direct.xml
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Check Firewalld Saved Rules
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Then enable the rule for it to take effect immediately:
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# firewall-cmd --direct --add-rule ipv4 filter FORWARD 0 -i enp0s3 -o enp0s8 -j ACCEPT
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Now you can telnet to the web server from the RHEL 7 box and run [tcpdump][3] again to monitor the TCP traffic between the two machines, this time with the firewall in router #2 enabled.
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# telnet 10.0.0.20 80
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# tcpdump -qnnvvv -i enp0s3 host 10.0.0.20
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What if you want to only allow incoming connections to the web server (port 80) from 192.168.0.18 and block connections from other sources in the 192.168.0.0/24 network?
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In the web server’s firewall, add the following rules:
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# firewall-cmd --add-rich-rule 'rule family="ipv4" source address="192.168.0.18/24" service name="http" accept'
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# firewall-cmd --add-rich-rule 'rule family="ipv4" source address="192.168.0.18/24" service name="http" accept' --permanent
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# firewall-cmd --add-rich-rule 'rule family="ipv4" source address="192.168.0.0/24" service name="http" drop'
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# firewall-cmd --add-rich-rule 'rule family="ipv4" source address="192.168.0.0/24" service name="http" drop' --permanent
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Now you can make HTTP requests to the web server, from 192.168.0.18 and from some other machine in 192.168.0.0/24. In the first case the connection should complete successfully, whereas in the second it will eventually timeout.
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To do so, any of the following commands will do the trick:
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# telnet 10.0.0.20 80
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# wget 10.0.0.20
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I strongly advise you to check out the [Firewalld Rich Language][4] documentation in the Fedora Project Wiki for further details on rich rules.
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### Network Address Translation in RHEL 7 ###
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Network Address Translation (NAT) is the process where a group of computers (it can also be just one of them) in a private network are assigned an unique public IP address. As result, they are still uniquely identified by their own private IP address inside the network but to the outside they all “seem” the same.
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In addition, NAT makes it possible that computers inside a network sends requests to outside resources (like the Internet) and have the corresponding responses be sent back to the source system only.
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Let’s now consider the following scenario:
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Network Address Translation
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In router #2, we will move the enp0s3 interface to the external zone, and enp0s8 to the internal zone, where masquerading, or NAT, is enabled by default:
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# firewall-cmd --list-all --zone=external
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# firewall-cmd --change-interface=enp0s3 --zone=external
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# firewall-cmd --change-interface=enp0s3 --zone=external --permanent
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# firewall-cmd --change-interface=enp0s8 --zone=internal
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# firewall-cmd --change-interface=enp0s8 --zone=internal --permanent
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For our current setup, the internal zone – along with everything that is enabled in it will be the default zone:
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# firewall-cmd --set-default-zone=internal
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Next, let’s reload firewall rules and keep state information:
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# firewall-cmd --reload
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Finally, let’s add router #2 as default gateway in the web server:
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# ip route add default via 10.0.0.18
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You can now verify that you can ping router #1 and an external site (tecmint.com, for example) from the web server:
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# ping -c 2 192.168.0.1
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# ping -c 2 tecmint.com
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Verify Network Routing
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### Setting Kernel Runtime Parameters in RHEL 7 ###
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In Linux, you are allowed to change, enable, and disable the kernel runtime parameters, and RHEL is no exception. The /proc/sys interface (sysctl) lets you set runtime parameters on-the-fly to modify the system’s behavior without much hassle when operating conditions change.
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To do so, the echo shell built-in is used to write to files inside /proc/sys/<category>, where <category> is most likely one of the following directories:
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- dev: parameters for specific devices connected to the machine.
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- fs: filesystem configuration (quotas and inodes, for example).
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- kernel: kernel-specific configuration.
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- net: network configuration.
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- vm: use of the kernel’s virtual memory.
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To display the list of all the currently available values, run
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# sysctl -a | less
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In Part 1, we changed the value of the net.ipv4.ip_forward parameter by doing
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# echo 1 > /proc/sys/net/ipv4/ip_forward
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in order to allow a Linux machine to act as router.
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Another runtime parameter that you may want to set is kernel.sysrq, which enables the Sysrq key in your keyboard to instruct the system to perform gracefully some low-level functions, such as rebooting the system if it has frozen for some reason:
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# echo 1 > /proc/sys/kernel/sysrq
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To display the value of a specific parameter, use sysctl as follows:
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# sysctl <parameter.name>
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For example,
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# sysctl net.ipv4.ip_forward
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# sysctl kernel.sysrq
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Some parameters, such as the ones mentioned above, require only one value, whereas others (for example, fs.inode-state) require multiple values:
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Check Kernel Parameters
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In either case, you need to read the kernel’s documentation before making any changes.
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Please note that these settings will go away when the system is rebooted. To make these changes permanent, we will need to add .conf files inside the /etc/sysctl.d as follows:
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# echo "net.ipv4.ip_forward = 1" > /etc/sysctl.d/10-forward.conf
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(where the number 10 indicates the order of processing relative to other files in the same directory).
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and enable the changes with
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# sysctl -p /etc/sysctl.d/10-forward.conf
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### Summary ###
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In this tutorial we have explained the basics of packet filtering, network address translation, and setting kernel runtime parameters on a running system and persistently across reboots. I hope you have found this information useful, and as always, we look forward to hearing from you!
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Don’t hesitate to share with us your questions, comments, or suggestions using the form below.
|
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--------------------------------------------------------------------------------
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via: http://www.tecmint.com/perform-packet-filtering-network-address-translation-and-set-kernel-runtime-parameters-in-rhel/
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作者：[Gabriel Cánepa][a]
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译者：[译者ID](https://github.com/译者ID)
|
||||
校对：[校对者ID](https://github.com/校对者ID)
|
||||
|
||||
本文由 [LCTT](https://github.com/LCTT/TranslateProject) 原创翻译，[Linux中国](https://linux.cn/) 荣誉推出
|
||||
|
||||
[a]:http://www.tecmint.com/author/gacanepa/
|
||||
[1]:http://www.tecmint.com/how-to-setup-and-configure-static-network-routing-in-rhel/
|
||||
[2]:http://www.tecmint.com/firewalld-rules-for-centos-7/
|
||||
[3]:http://www.tecmint.com/12-tcpdump-commands-a-network-sniffer-tool/
|
||||
[4]:https://fedoraproject.org/wiki/Features/FirewalldRichLanguage
|
||||
@ -0,0 +1,182 @@
|
||||
Part 3 - How to Produce and Deliver System Activity Reports Using Linux Toolsets
|
||||
================================================================================
|
||||
As a system engineer, you will often need to produce reports that show the utilization of your system’s resources in order to make sure that: 1) they are being utilized optimally, 2) prevent bottlenecks, and 3) ensure scalability, among other reasons.
|
||||
|
||||
|
||||
|
||||
RHCE: Monitor Linux Performance Activity Reports – Part 3
|
||||
|
||||
Besides the well-known native Linux tools that are used to check disk, memory, and CPU usage – to name a few examples, Red Hat Enterprise Linux 7 provides two additional toolsets to enhance the data you can collect for your reports: sysstat and dstat.
|
||||
|
||||
In this article we will describe both, but let’s first start by reviewing the usage of the classic tools.
|
||||
|
||||
### Native Linux Tools ###
|
||||
|
||||
With df, you will be able to report disk space and inode usage of by filesystem. You need to monitor both because a lack of space will prevent you from being able to save further files (and may even cause the system to crash), just like running out of inodes will mean you can’t link further files with their corresponding data structures, thus producing the same effect: you won’t be able to save those files to disk.
|
||||
|
||||
# df -h [Display output in human-readable form]
|
||||
# df -h --total [Produce a grand total]
|
||||
|
||||
|
||||
|
||||
Check Linux Total Disk Usage
|
||||
|
||||
# df -i [Show inode count by filesystem]
|
||||
# df -i --total [Produce a grand total]
|
||||
|
||||
|
||||
|
||||
Check Linux Total inode Numbers
|
||||
|
||||
With du, you can estimate file space usage by either file, directory, or filesystem.
|
||||
|
||||
For example, let’s see how much space is used by the /home directory, which includes all of the user’s personal files. The first command will return the overall space currently used by the entire /home directory, whereas the second will also display a disaggregated list by sub-directory as well:
|
||||
|
||||
# du -sch /home
|
||||
# du -sch /home/*
|
||||
|
||||
|
||||
|
||||
Check Linux Directory Disk Size
|
||||
|
||||
Don’t Miss:
|
||||
|
||||
- [12 ‘df’ Command Examples to Check Linux Disk Space Usage][1]
|
||||
- [10 ‘du’ Command Examples to Find Disk Usage of Files/Directories][2]
|
||||
|
||||
Another utility that can’t be missing from your toolset is vmstat. It will allow you to see at a quick glance information about processes, CPU and memory usage, disk activity, and more.
|
||||
|
||||
If run without arguments, vmstat will return averages since the last reboot. While you may use this form of the command once in a while, it will be more helpful to take a certain amount of system utilization samples, one after another, with a defined time separation between samples.
|
||||
|
||||
For example,
|
||||
|
||||
# vmstat 5 10
|
||||
|
||||
will return 10 samples taken every 5 seconds:
|
||||
|
||||
|
||||
|
||||
Check Linux System Performance
|
||||
|
||||
As you can see in the above picture, the output of vmstat is divided by columns: procs (processes), memory, swap, io, system, and cpu. The meaning of each field can be found in the FIELD DESCRIPTION sections in the man page of vmstat.
|
||||
|
||||
Where can vmstat come in handy? Let’s examine the behavior of the system before and during a yum update:
|
||||
|
||||
# vmstat -a 1 5
|
||||
|
||||
|
||||
|
||||
Vmstat Linux Performance Monitoring
|
||||
|
||||
Please note that as files are being modified on disk, the amount of active memory increases and so does the number of blocks written to disk (bo) and the CPU time that is dedicated to user processes (us).
|
||||
|
||||
Or during the saving process of a large file directly to disk (caused by dsync):
|
||||
|
||||
# vmstat -a 1 5
|
||||
# dd if=/dev/zero of=dummy.out bs=1M count=1000 oflag=dsync
|
||||
|
||||
|
||||
|
||||
VmStat Linux Disk Performance Monitoring
|
||||
|
||||
In this case, we can see a yet larger number of blocks being written to disk (bo), which was to be expected, but also an increase of the amount of CPU time that it has to wait for I/O operations to complete before processing tasks (wa).
|
||||
|
||||
**Don’t Miss**: [Vmstat – Linux Performance Monitoring][3]
|
||||
|
||||
### Other Linux Tools ###
|
||||
|
||||
As mentioned in the introduction of this chapter, there are other tools that you can use to check the system status and utilization (they are not only provided by Red Hat but also by other major distributions from their officially supported repositories).
|
||||
|
||||
The sysstat package contains the following utilities:
|
||||
|
||||
- sar (collect, report, or save system activity information).
|
||||
- sadf (display data collected by sar in multiple formats).
|
||||
- mpstat (report processors related statistics).
|
||||
- iostat (report CPU statistics and I/O statistics for devices and partitions).
|
||||
- pidstat (report statistics for Linux tasks).
|
||||
- nfsiostat (report input/output statistics for NFS).
|
||||
- cifsiostat (report CIFS statistics) and
|
||||
- sa1 (collect and store binary data in the system activity daily data file.
|
||||
- sa2 (write a daily report in the /var/log/sa directory) tools.
|
||||
|
||||
whereas dstat adds some extra features to the functionality provided by those tools, along with more counters and flexibility. You can find an overall description of each tool by running yum info sysstat or yum info dstat, respectively, or checking the individual man pages after installation.
|
||||
|
||||
To install both packages:
|
||||
|
||||
# yum update && yum install sysstat dstat
|
||||
|
||||
The main configuration file for sysstat is /etc/sysconfig/sysstat. You will find the following parameters in that file:
|
||||
|
||||
# How long to keep log files (in days).
|
||||
# If value is greater than 28, then log files are kept in
|
||||
# multiple directories, one for each month.
|
||||
HISTORY=28
|
||||
# Compress (using gzip or bzip2) sa and sar files older than (in days):
|
||||
COMPRESSAFTER=31
|
||||
# Parameters for the system activity data collector (see sadc manual page)
|
||||
# which are used for the generation of log files.
|
||||
SADC_OPTIONS="-S DISK"
|
||||
# Compression program to use.
|
||||
ZIP="bzip2"
|
||||
|
||||
When sysstat is installed, two cron jobs are added and enabled in /etc/cron.d/sysstat. The first job runs the system activity accounting tool every 10 minutes and stores the reports in /var/log/sa/saXX where XX is the day of the month.
|
||||
|
||||
Thus, /var/log/sa/sa05 will contain all the system activity reports from the 5th of the month. This assumes that we are using the default value in the HISTORY variable in the configuration file above:
|
||||
|
||||
*/10 * * * * root /usr/lib64/sa/sa1 1 1
|
||||
|
||||
The second job generates a daily summary of process accounting at 11:53 pm every day and stores it in /var/log/sa/sarXX files, where XX has the same meaning as in the previous example:
|
||||
|
||||
53 23 * * * root /usr/lib64/sa/sa2 -A
|
||||
|
||||
For example, you may want to output system statistics from 9:30 am through 5:30 pm of the sixth of the month to a .csv file that can easily be viewed using LibreOffice Calc or Microsoft Excel (this approach will also allow you to create charts or graphs):
|
||||
|
||||
# sadf -s 09:30:00 -e 17:30:00 -dh /var/log/sa/sa06 -- | sed 's/;/,/g' > system_stats20150806.csv
|
||||
|
||||
You could alternatively use the -j flag instead of -d in the sadf command above to output the system stats in JSON format, which could be useful if you need to consume the data in a web application, for example.
|
||||
|
||||
|
||||
|
||||
Linux System Statistics
|
||||
|
||||
Finally, let’s see what dstat has to offer. Please note that if run without arguments, dstat assumes -cdngy by default (short for CPU, disk, network, memory pages, and system stats, respectively), and adds one line every second (execution can be interrupted anytime with Ctrl + C):
|
||||
|
||||
# dstat
|
||||
|
||||
|
||||
|
||||
Linux Disk Statistics Monitoring
|
||||
|
||||
To output the stats to a .csv file, use the –output flag followed by a file name. Let’s see how this looks on LibreOffice Calc:
|
||||
|
||||
|
||||
|
||||
Monitor Linux Statistics Output
|
||||
|
||||
I strongly advise you to check out the man page of dstat, included with this article along with the man page of sysstat in PDF format for your reading convenience. You will find several other options that will help you create custom and detailed system activity reports.
|
||||
|
||||
**Don’t Miss**: [Sysstat – Linux Usage Activity Monitoring Tool][4]
|
||||
|
||||
### Summary ###
|
||||
|
||||
In this guide we have explained how to use both native Linux tools and specific utilities provided with RHEL 7 in order to produce reports on system utilization. At one point or another, you will come to rely on these reports as best friends.
|
||||
|
||||
You will probably have used other tools that we have not covered in this tutorial. If so, feel free to share them with the rest of the community along with any other suggestions / questions / comments that you may have- using the form below.
|
||||
|
||||
We look forward to hearing from you.
|
||||
|
||||
--------------------------------------------------------------------------------
|
||||
|
||||
via: http://www.tecmint.com/linux-performance-monitoring-and-file-system-statistics-reports/
|
||||
|
||||
作者：[Gabriel Cánepa][a]
|
||||
译者：[译者ID](https://github.com/译者ID)
|
||||
校对：[校对者ID](https://github.com/校对者ID)
|
||||
|
||||
本文由 [LCTT](https://github.com/LCTT/TranslateProject) 原创翻译，[Linux中国](https://linux.cn/) 荣誉推出
|
||||
|
||||
[a]:http://www.tecmint.com/author/gacanepa/
|
||||
[1]:http://www.tecmint.com/how-to-check-disk-space-in-linux/
|
||||
[2]:http://www.tecmint.com/check-linux-disk-usage-of-files-and-directories/
|
||||
[3]:http://www.tecmint.com/linux-performance-monitoring-with-vmstat-and-iostat-commands/
|
||||
[4]:http://www.tecmint.com/install-sysstat-in-linux/
|
||||
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Reference in New Issue
Block a user