mirror of
https://github.com/LCTT/TranslateProject.git
synced 2025-02-25 00:50:15 +08:00
Xingyu.Wang
commit
0acb12edd8
@ -1,321 +0,0 @@
|
||||
struggling 翻译中
|
||||
Setup RAID Level 6 (Striping with Double Distributed Parity) in Linux – Part 5
|
||||
================================================================================
|
||||
RAID 6 is upgraded version of RAID 5, where it has two distributed parity which provides fault tolerance even after two drives fails. Mission critical system still operational incase of two concurrent disks failures. It’s alike RAID 5, but provides more robust, because it uses one more disk for parity.
|
||||
|
||||
In our earlier article, we’ve seen distributed parity in RAID 5, but in this article we will going to see RAID 6 with double distributed parity. Don’t expect extra performance than any other RAID, if so we have to install a dedicated RAID Controller too. Here in RAID 6 even if we loose our 2 disks we can get the data back by replacing a spare drive and build it from parity.
|
||||
|
||||
|
||||
|
||||
Setup RAID 6 in Linux
|
||||
|
||||
To setup a RAID 6, minimum 4 numbers of disks or more in a set are required. RAID 6 have multiple disks even in some set it may be have some bunch of disks, while reading, it will read from all the drives, so reading would be faster whereas writing would be poor because it has to stripe over multiple disks.
|
||||
|
||||
Now, many of us comes to conclusion, why we need to use RAID 6, when it doesn’t perform like any other RAID. Hmm… those who raise this question need to know that, if they need high fault tolerance choose RAID 6. In every higher environments with high availability for database, they use RAID 6 because database is the most important and need to be safe in any cost, also it can be useful for video streaming environments.
|
||||
|
||||
#### Pros and Cons of RAID 6 ####
|
||||
|
||||
- Performance are good.
|
||||
- RAID 6 is expensive, as it requires two independent drives are used for parity functions.
|
||||
- Will loose a two disks capacity for using parity information (double parity).
|
||||
- No data loss, even after two disk fails. We can rebuilt from parity after replacing the failed disk.
|
||||
- Reading will be better than RAID 5, because it reads from multiple disk, But writing performance will be very poor without dedicated RAID Controller.
|
||||
|
||||
#### Requirements ####
|
||||
|
||||
Minimum 4 numbers of disks are required to create a RAID 6. If you want to add more disks, you can, but you must have dedicated raid controller. In software RAID, we will won’t get better performance in RAID 6. So we need a physical RAID controller.
|
||||
|
||||
Those who are new to RAID setup, we recommend to go through RAID articles below.
|
||||
|
||||
- [Basic Concepts of RAID in Linux – Part 1][1]
|
||||
- [Creating Software RAID 0 (Stripe) in Linux – Part 2][2]
|
||||
- [Setting up RAID 1 (Mirroring) in Linux – Part 3][3]
|
||||
|
||||
#### My Server Setup ####
|
||||
|
||||
Operating System : CentOS 6.5 Final
|
||||
IP Address : 192.168.0.228
|
||||
Hostname : rd6.tecmintlocal.com
|
||||
Disk 1 [20GB] : /dev/sdb
|
||||
Disk 2 [20GB] : /dev/sdc
|
||||
Disk 3 [20GB] : /dev/sdd
|
||||
Disk 4 [20GB] : /dev/sde
|
||||
|
||||
This article is a Part 5 of a 9-tutorial RAID series, here we are going to see how we can create and setup Software RAID 6 or Striping with Double Distributed Parity in Linux systems or servers using four 20GB disks named /dev/sdb, /dev/sdc, /dev/sdd and /dev/sde.
|
||||
|
||||
### Step 1: Installing mdadm Tool and Examine Drives ###
|
||||
|
||||
1. If you’re following our last two Raid articles (Part 2 and Part 3), where we’ve already shown how to install ‘mdadm‘ tool. If you’re new to this article, let me explain that ‘mdadm‘ is a tool to create and manage Raid in Linux systems, let’s install the tool using following command according to your Linux distribution.
|
||||
|
||||
# yum install mdadm [on RedHat systems]
|
||||
# apt-get install mdadm [on Debain systems]
|
||||
|
||||
2. After installing the tool, now it’s time to verify the attached four drives that we are going to use for raid creation using the following ‘fdisk‘ command.
|
||||
|
||||
# fdisk -l | grep sd
|
||||
|
||||
|
||||
|
||||
Check Disks in Linux
|
||||
|
||||
3. Before creating a RAID drives, always examine our disk drives whether there is any RAID is already created on the disks.
|
||||
|
||||
# mdadm -E /dev/sd[b-e]
|
||||
# mdadm --examine /dev/sdb /dev/sdc /dev/sdd /dev/sde
|
||||
|
||||
|
||||
|
||||
Check Raid on Disk
|
||||
|
||||
**Note**: In the above image depicts that there is no any super-block detected or no RAID is defined in four disk drives. We may move further to start creating RAID 6.
|
||||
|
||||
### Step 2: Drive Partitioning for RAID 6 ###
|
||||
|
||||
4. Now create partitions for raid on ‘/dev/sdb‘, ‘/dev/sdc‘, ‘/dev/sdd‘ and ‘/dev/sde‘ with the help of following fdisk command. Here, we will show how to create partition on sdb drive and later same steps to be followed for rest of the drives.
|
||||
|
||||
**Create /dev/sdb Partition**
|
||||
|
||||
# fdisk /dev/sdb
|
||||
|
||||
Please follow the instructions as shown below for creating partition.
|
||||
|
||||
- Press ‘n‘ for creating new partition.
|
||||
- Then choose ‘P‘ for Primary partition.
|
||||
- Next choose the partition number as 1.
|
||||
- Define the default value by just pressing two times Enter key.
|
||||
- Next press ‘P‘ to print the defined partition.
|
||||
- Press ‘L‘ to list all available types.
|
||||
- Type ‘t‘ to choose the partitions.
|
||||
- Choose ‘fd‘ for Linux raid auto and press Enter to apply.
|
||||
- Then again use ‘P‘ to print the changes what we have made.
|
||||
- Use ‘w‘ to write the changes.
|
||||
|
||||
|
||||
|
||||
Create /dev/sdb Partition
|
||||
|
||||
**Create /dev/sdb Partition**
|
||||
|
||||
# fdisk /dev/sdc
|
||||
|
||||
|
||||
|
||||
Create /dev/sdc Partition
|
||||
|
||||
**Create /dev/sdd Partition**
|
||||
|
||||
# fdisk /dev/sdd
|
||||
|
||||
|
||||
|
||||
Create /dev/sdd Partition
|
||||
|
||||
**Create /dev/sde Partition**
|
||||
|
||||
# fdisk /dev/sde
|
||||
|
||||
|
||||
|
||||
Create /dev/sde Partition
|
||||
|
||||
5. After creating partitions, it’s always good habit to examine the drives for super-blocks. If super-blocks does not exist than we can go head to create a new RAID setup.
|
||||
|
||||
# mdadm -E /dev/sd[b-e]1
|
||||
|
||||
|
||||
or
|
||||
|
||||
# mdadm --examine /dev/sdb1 /dev/sdc1 /dev/sdd1 /dev/sde1
|
||||
|
||||
|
||||
|
||||
Check Raid on New Partitions
|
||||
|
||||
### Step 3: Creating md device (RAID) ###
|
||||
|
||||
6. Now it’s time to create Raid device ‘md0‘ (i.e. /dev/md0) and apply raid level on all newly created partitions and confirm the raid using following commands.
|
||||
|
||||
# mdadm --create /dev/md0 --level=6 --raid-devices=4 /dev/sdb1 /dev/sdc1 /dev/sdd1 /dev/sde1
|
||||
# cat /proc/mdstat
|
||||
|
||||
|
||||
|
||||
Create Raid 6 Device
|
||||
|
||||
7. You can also check the current process of raid using watch command as shown in the screen grab below.
|
||||
|
||||
# watch -n1 cat /proc/mdstat
|
||||
|
||||
|
||||
|
||||
Check Raid 6 Process
|
||||
|
||||
8. Verify the raid devices using the following command.
|
||||
|
||||
# mdadm -E /dev/sd[b-e]1
|
||||
|
||||
**Note**:: The above command will be display the information of the four disks, which is quite long so not possible to post the output or screen grab here.
|
||||
|
||||
9. Next, verify the RAID array to confirm that the re-syncing is started.
|
||||
|
||||
# mdadm --detail /dev/md0
|
||||
|
||||
|
||||
|
||||
Check Raid 6 Array
|
||||
|
||||
### Step 4: Creating FileSystem on Raid Device ###
|
||||
|
||||
10. Create a filesystem using ext4 for ‘/dev/md0‘ and mount it under /mnt/raid5. Here we’ve used ext4, but you can use any type of filesystem as per your choice.
|
||||
|
||||
# mkfs.ext4 /dev/md0
|
||||
|
||||
|
||||
|
||||
Create File System on Raid 6
|
||||
|
||||
11. Mount the created filesystem under /mnt/raid6 and verify the files under mount point, we can see lost+found directory.
|
||||
|
||||
# mkdir /mnt/raid6
|
||||
# mount /dev/md0 /mnt/raid6/
|
||||
# ls -l /mnt/raid6/
|
||||
|
||||
12. Create some files under mount point and append some text in any one of the file to verify the content.
|
||||
|
||||
# touch /mnt/raid6/raid6_test.txt
|
||||
# ls -l /mnt/raid6/
|
||||
# echo "tecmint raid setups" > /mnt/raid6/raid6_test.txt
|
||||
# cat /mnt/raid6/raid6_test.txt
|
||||
|
||||
|
||||
|
||||
Verify Raid Content
|
||||
|
||||
13. Add an entry in /etc/fstab to auto mount the device at the system startup and append the below entry, mount point may differ according to your environment.
|
||||
|
||||
# vim /etc/fstab
|
||||
|
||||
/dev/md0 /mnt/raid6 ext4 defaults 0 0
|
||||
|
||||
|
||||
|
||||
Automount Raid 6 Device
|
||||
|
||||
14. Next, execute ‘mount -a‘ command to verify whether there is any error in fstab entry.
|
||||
|
||||
# mount -av
|
||||
|
||||
|
||||
|
||||
Verify Raid Automount
|
||||
|
||||
### Step 5: Save RAID 6 Configuration ###
|
||||
|
||||
15. Please note by default RAID don’t have a config file. We have to save it by manually using below command and then verify the status of device ‘/dev/md0‘.
|
||||
|
||||
# mdadm --detail --scan --verbose >> /etc/mdadm.conf
|
||||
# mdadm --detail /dev/md0
|
||||
|
||||
|
||||
|
||||
Save Raid 6 Configuration
|
||||
|
||||
|
||||
|
||||
Check Raid 6 Status
|
||||
|
||||
### Step 6: Adding a Spare Drives ###
|
||||
|
||||
16. Now it has 4 disks and there are two parity information’s available. In some cases, if any one of the disk fails we can get the data, because there is double parity in RAID 6.
|
||||
|
||||
May be if the second disk fails, we can add a new one before loosing third disk. It is possible to add a spare drive while creating our RAID set, But I have not defined the spare drive while creating our raid set. But, we can add a spare drive after any drive failure or while creating the RAID set. Now we have already created the RAID set now let me add a spare drive for demonstration.
|
||||
|
||||
For the demonstration purpose, I’ve hot-plugged a new HDD disk (i.e. /dev/sdf), let’s verify the attached disk.
|
||||
|
||||
# ls -l /dev/ | grep sd
|
||||
|
||||
|
||||
|
||||
Check New Disk
|
||||
|
||||
17. Now again confirm the new attached disk for any raid is already configured or not using the same mdadm command.
|
||||
|
||||
# mdadm --examine /dev/sdf
|
||||
|
||||
|
||||
|
||||
Check Raid on New Disk
|
||||
|
||||
**Note**: As usual, like we’ve created partitions for four disks earlier, similarly we’ve to create new partition on the new plugged disk using fdisk command.
|
||||
|
||||
# fdisk /dev/sdf
|
||||
|
||||
|
||||
|
||||
Create /dev/sdf Partition
|
||||
|
||||
18. Again after creating new partition on /dev/sdf, confirm the raid on the partition, include the spare drive to the /dev/md0 raid device and verify the added device.
|
||||
|
||||
# mdadm --examine /dev/sdf
|
||||
# mdadm --examine /dev/sdf1
|
||||
# mdadm --add /dev/md0 /dev/sdf1
|
||||
# mdadm --detail /dev/md0
|
||||
|
||||
|
||||
|
||||
Verify Raid on sdf Partition
|
||||
|
||||
|
||||
|
||||
Add sdf Partition to Raid
|
||||
|
||||
|
||||
|
||||
Verify sdf Partition Details
|
||||
|
||||
### Step 7: Check Raid 6 Fault Tolerance ###
|
||||
|
||||
19. Now, let us check whether spare drive works automatically, if anyone of the disk fails in our Array. For testing, I’ve personally marked one of the drive is failed.
|
||||
|
||||
Here, we’re going to mark /dev/sdd1 as failed drive.
|
||||
|
||||
# mdadm --manage --fail /dev/md0 /dev/sdd1
|
||||
|
||||
|
||||
|
||||
Check Raid 6 Fault Tolerance
|
||||
|
||||
20. Let me get the details of RAID set now and check whether our spare started to sync.
|
||||
|
||||
# mdadm --detail /dev/md0
|
||||
|
||||
|
||||
|
||||
Check Auto Raid Syncing
|
||||
|
||||
**Hurray!** Here, we can see the spare got activated and started rebuilding process. At the bottom we can see the faulty drive /dev/sdd1 listed as faulty. We can monitor build process using following command.
|
||||
|
||||
# cat /proc/mdstat
|
||||
|
||||
|
||||
|
||||
Raid 6 Auto Syncing
|
||||
|
||||
### Conclusion: ###
|
||||
|
||||
Here, we have seen how to setup RAID 6 using four disks. This RAID level is one of the expensive setup with high redundancy. We will see how to setup a Nested RAID 10 and much more in the next articles. Till then, stay connected with TECMINT.
|
||||
|
||||
--------------------------------------------------------------------------------
|
||||
|
||||
via: http://www.tecmint.com/create-raid-6-in-linux/
|
||||
|
||||
作者：[Babin Lonston][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/babinlonston/
|
||||
[1]:http://www.tecmint.com/understanding-raid-setup-in-linux/
|
||||
[2]:http://www.tecmint.com/create-raid0-in-linux/
|
||||
[3]:http://www.tecmint.com/create-raid1-in-linux/
|
||||
@ -0,0 +1,321 @@
|
||||
|
||||
在 Linux 中安装 RAID 6（条带化双分布式奇偶校验） - 第5部分
|
||||
================================================================================
|
||||
RAID 6 是 RAID 5 的升级版，它有两个分布式奇偶校验，即时两个磁盘发生故障后依然有容错能力。两并列的磁盘发生故障时，系统的关键任务仍然能运行。它与 RAID 5 相似，但性能更健壮，因为它多用了一个磁盘来进行奇偶校验。
|
||||
|
||||
在之前的文章中，我们已经在 RAID 5 看了分布式奇偶校验，但在本文中，我们将看到的是 RAID 6 双分布式奇偶校验。不要期望比其他 RAID 有额外的性能，我们仍然需要安装一个专用的 RAID 控制器。在 RAID 6 中，即使我们失去了2个磁盘，我们仍可以取回数据通过更换磁盘，然后从校验中构建数据。
|
||||
|
||||
|
||||
|
||||
在 Linux 中安装 RAID 6
|
||||
|
||||
要建立一个 RAID 6，一组最少需要4个磁盘。RAID 6 甚至在有些设定中会有多组磁盘，当读取数据时，它会同时从所有磁盘读取，所以读取速度会更快，当写数据时，因为它要将数据写在条带化的多个磁盘上，所以性能会较差。
|
||||
|
||||
现在，很多人都在讨论为什么我们需要使用 RAID 6，它的性能和其他 RAID 相比并不太好。提出这个问题首先需要知道的是，如果需要高容错的必须选择 RAID 6。在每一个对数据库的高可用性要求较高的环境中，他们需要 RAID 6 因为数据库是最重要，无论花费多少都需要保护其安全，它在视频流环境中也是非常有用的。
|
||||
|
||||
#### RAID 6 的的优点和缺点 ####
|
||||
|
||||
- 性能很不错。
|
||||
- RAID 6 非常昂贵，因为它要求两个独立的磁盘用于奇偶校验功能。
|
||||
- 将失去两个磁盘的容量来保存奇偶校验信息（双奇偶校验）。
|
||||
- 不存在数据丢失，即时两个磁盘损坏。我们可以在更换损坏的磁盘后从校验中重建数据。
|
||||
- 读性能比 RAID 5 更好，因为它从多个磁盘读取，但对于没有专用的 RAID 控制器的设备写性能将非常差。
|
||||
|
||||
#### 要求 ####
|
||||
|
||||
要创建一个 RAID 6 最少需要4个磁盘.你也可以添加更多的磁盘，但你必须有专用的 RAID 控制器。在软件 RAID 中，我们在 RAID 6 中不会得到更好的性能，所以我们需要一个物理 RAID 控制器。
|
||||
|
||||
这些是新建一个 RAID 需要的设置，我们建议先看完以下 RAID 文章。
|
||||
|
||||
- [Linux 中 RAID 的基本概念 – 第一部分][1]
|
||||
- [在 Linux 上创建软件 RAID 0 (条带化) – 第二部分][2]
|
||||
- [在 Linux 上创建软件 RAID 1 (镜像) – 第三部分][3]
|
||||
|
||||
#### My Server Setup ####
|
||||
|
||||
Operating System : CentOS 6.5 Final
|
||||
IP Address : 192.168.0.228
|
||||
Hostname : rd6.tecmintlocal.com
|
||||
Disk 1 [20GB] : /dev/sdb
|
||||
Disk 2 [20GB] : /dev/sdc
|
||||
Disk 3 [20GB] : /dev/sdd
|
||||
Disk 4 [20GB] : /dev/sde
|
||||
|
||||
这篇文章是9系列 RAID 教程的第5部分，在这里我们将看到我们如何在 Linux 系统或者服务器上创建和设置软件 RAID 6 或条带化双分布式奇偶校验，使用四个 20GB 的磁盘 /dev/sdb, /dev/sdc, /dev/sdd 和 /dev/sde.
|
||||
|
||||
### 第1步：安装 mdadm 工具，并检查磁盘 ###
|
||||
|
||||
1.如果你按照我们最进的两篇 RAID 文章（第2篇和第3篇），我们已经展示了如何安装‘mdadm‘工具。如果你直接看的这篇文章，我们先来解释下在Linux系统中如何使用‘mdadm‘工具来创建和管理 RAID，首先根据你的 Linux 发行版使用以下命令来安装。
|
||||
|
||||
# yum install mdadm [on RedHat systems]
|
||||
# apt-get install mdadm [on Debain systems]
|
||||
|
||||
2.安装该工具后，然后来验证需要的四个磁盘，我们将会使用下面的‘fdisk‘命令来检验用于创建 RAID 的磁盘。
|
||||
|
||||
# fdisk -l | grep sd
|
||||
|
||||
|
||||
|
||||
在 Linux 中检查磁盘
|
||||
|
||||
3.在创建 RAID 磁盘前，先检查下我们的磁盘是否创建过 RAID 分区。
|
||||
|
||||
# mdadm -E /dev/sd[b-e]
|
||||
# mdadm --examine /dev/sdb /dev/sdc /dev/sdd /dev/sde
|
||||
|
||||
|
||||
|
||||
在磁盘上检查 Raid 分区
|
||||
|
||||
**注意**: 在上面的图片中，没有检测到任何 super-block 或者说在四个磁盘上没有 RAID 存在。现在我们开始创建 RAID 6。
|
||||
|
||||
### 第2步：为 RAID 6 创建磁盘分区 ###
|
||||
|
||||
4.现在为 raid 创建分区‘/dev/sdb‘, ‘/dev/sdc‘, ‘/dev/sdd‘ 和 ‘/dev/sde‘使用下面 fdisk 命令。在这里，我们将展示如何创建分区在 sdb 磁盘，同样的步骤也适用于其他分区。
|
||||
|
||||
**创建 /dev/sdb 分区**
|
||||
|
||||
# fdisk /dev/sdb
|
||||
|
||||
请按照说明进行操作，如下图所示创建分区。
|
||||
|
||||
- 按 ‘n’ 创建新的分区。
|
||||
- 然后按 ‘P’ 选择主分区。
|
||||
- 接下来选择分区号为1。
|
||||
- 只需按两次回车键选择默认值即可。
|
||||
- 然后，按 ‘P’ 来打印创建好的分区。
|
||||
- 按 ‘L’，列出所有可用的类型。
|
||||
- 按 ‘t’ 去修改分区。
|
||||
- 键入 ‘fd’ 设置为 Linux 的 RAID 类型，然后按 Enter 确认。
|
||||
- 然后再次使用‘p’查看我们所做的更改。
|
||||
- 使用‘w’保存更改。
|
||||
|
||||
|
||||
|
||||
创建 /dev/sdb 分区
|
||||
|
||||
**创建 /dev/sdc 分区**
|
||||
|
||||
# fdisk /dev/sdc
|
||||
|
||||
|
||||
|
||||
创建 /dev/sdc 分区
|
||||
|
||||
**创建 /dev/sdd 分区**
|
||||
|
||||
# fdisk /dev/sdd
|
||||
|
||||
|
||||
|
||||
创建 /dev/sdd 分区
|
||||
|
||||
**创建 /dev/sde 分区**
|
||||
|
||||
# fdisk /dev/sde
|
||||
|
||||
|
||||
|
||||
创建 /dev/sde 分区
|
||||
|
||||
5.创建好分区后，检查磁盘的 super-blocks 是个好的习惯。如果 super-blocks 不存在我们可以按前面的创建一个新的 RAID。
|
||||
|
||||
# mdadm -E /dev/sd[b-e]1
|
||||
|
||||
|
||||
或者
|
||||
|
||||
# mdadm --examine /dev/sdb1 /dev/sdc1 /dev/sdd1 /dev/sde1
|
||||
|
||||
|
||||
|
||||
在新分区中检查 Raid
|
||||
|
||||
### 步骤3：创建 md 设备（RAID） ###
|
||||
|
||||
6，现在是时候来创建 RAID 设备‘md0‘ （即 /dev/md0）并应用 RAID 级别在所有新创建的分区中，确认 raid 使用以下命令。
|
||||
|
||||
# mdadm --create /dev/md0 --level=6 --raid-devices=4 /dev/sdb1 /dev/sdc1 /dev/sdd1 /dev/sde1
|
||||
# cat /proc/mdstat
|
||||
|
||||
|
||||
|
||||
创建 Raid 6 设备
|
||||
|
||||
7.你还可以使用 watch 命令来查看当前 raid 的进程，如下图所示。
|
||||
|
||||
# watch -n1 cat /proc/mdstat
|
||||
|
||||
|
||||
|
||||
检查 Raid 6 进程
|
||||
|
||||
8.使用以下命令验证 RAID 设备。
|
||||
|
||||
# mdadm -E /dev/sd[b-e]1
|
||||
|
||||
**注意**::上述命令将显示四个磁盘的信息，这是相当长的，所以没有截取其完整的输出。
|
||||
|
||||
9.接下来，验证 RAID 阵列，以确认 re-syncing 被启动。
|
||||
|
||||
# mdadm --detail /dev/md0
|
||||
|
||||
|
||||
|
||||
检查 Raid 6 阵列
|
||||
|
||||
### 第4步：在 RAID 设备上创建文件系统 ###
|
||||
|
||||
10.使用 ext4 为‘/dev/md0‘创建一个文件系统并将它挂载在 /mnt/raid5 。这里我们使用的是 ext4，但你可以根据你的选择使用任意类型的文件系统。
|
||||
|
||||
# mkfs.ext4 /dev/md0
|
||||
|
||||
|
||||
|
||||
在 Raid 6 上创建文件系统
|
||||
|
||||
11.挂载创建的文件系统到 /mnt/raid6，并验证挂载点下的文件，我们可以看到 lost+found 目录。
|
||||
|
||||
# mkdir /mnt/raid6
|
||||
# mount /dev/md0 /mnt/raid6/
|
||||
# ls -l /mnt/raid6/
|
||||
|
||||
12.在挂载点下创建一些文件，在任意文件中添加一些文字并验证其内容。
|
||||
|
||||
# touch /mnt/raid6/raid6_test.txt
|
||||
# ls -l /mnt/raid6/
|
||||
# echo "tecmint raid setups" > /mnt/raid6/raid6_test.txt
|
||||
# cat /mnt/raid6/raid6_test.txt
|
||||
|
||||
|
||||
|
||||
验证 Raid 内容
|
||||
|
||||
13.在 /etc/fstab 中添加以下条目使系统启动时自动挂载设备，环境不同挂载点可能会有所不同。
|
||||
|
||||
# vim /etc/fstab
|
||||
|
||||
/dev/md0 /mnt/raid6 ext4 defaults 0 0
|
||||
|
||||
|
||||
|
||||
自动挂载 Raid 6 设备
|
||||
|
||||
14.接下来，执行‘mount -a‘命令来验证 fstab 中的条目是否有错误。
|
||||
|
||||
# mount -av
|
||||
|
||||
|
||||
|
||||
验证 Raid 是否自动挂载
|
||||
|
||||
### 第5步：保存 RAID 6 的配置 ###
|
||||
|
||||
15.请注意默认 RAID 没有配置文件。我们需要使用以下命令手动保存它，然后检查设备‘/dev/md0‘的状态。
|
||||
|
||||
# mdadm --detail --scan --verbose >> /etc/mdadm.conf
|
||||
# mdadm --detail /dev/md0
|
||||
|
||||
|
||||
|
||||
保存 Raid 6 配置
|
||||
|
||||
|
||||
|
||||
检查 Raid 6 状态
|
||||
|
||||
### 第6步：添加备用磁盘 ###
|
||||
|
||||
16.现在，它使用了4个磁盘，并且有两个作为奇偶校验信息来使用。在某些情况下，如果任意一个磁盘出现故障，我们仍可以得到数据，因为在 RAID 6 使用双奇偶校验。
|
||||
|
||||
如果第二个磁盘也出现故障，在第三块磁盘损坏前我们可以添加一个新的。它可以作为一个备用磁盘并入 RAID 集合，但我在创建 raid 集合前没有定义备用的磁盘。但是，在磁盘损坏后或者创建 RAId 集合时我们可以添加一块磁盘。现在，我们已经创建好了 RAID，下面让我演示如何添加备用磁盘。
|
||||
|
||||
为了达到演示的目的，我已经热插入了一个新的 HDD 磁盘（即 /dev/sdf），让我们来验证接入的磁盘。
|
||||
|
||||
# ls -l /dev/ | grep sd
|
||||
|
||||
|
||||
|
||||
检查新 Disk
|
||||
|
||||
17.现在再次确认新连接的磁盘没有配置过 RAID ，使用 mdadm 来检查。
|
||||
|
||||
# mdadm --examine /dev/sdf
|
||||
|
||||
|
||||
|
||||
在新磁盘中检查 Raid
|
||||
|
||||
**注意**: 像往常一样，我们早前已经为四个磁盘创建了分区，同样，我们使用 fdisk 命令为新插入的磁盘创建新分区。
|
||||
|
||||
# fdisk /dev/sdf
|
||||
|
||||
|
||||
|
||||
为 /dev/sdf 创建分区
|
||||
|
||||
18.在 /dev/sdf 创建新的分区后，在新分区上确认 raid，包括/dev/md0 raid 设备的备用磁盘，并验证添加的设备。
|
||||
|
||||
# mdadm --examine /dev/sdf
|
||||
# mdadm --examine /dev/sdf1
|
||||
# mdadm --add /dev/md0 /dev/sdf1
|
||||
# mdadm --detail /dev/md0
|
||||
|
||||
|
||||
|
||||
在 sdf 分区上验证 Raid
|
||||
|
||||
|
||||
|
||||
为 RAID 添加 sdf 分区
|
||||
|
||||
|
||||
|
||||
验证 sdf 分区信息
|
||||
|
||||
### 第7步：检查 RAID 6 容错 ###
|
||||
|
||||
19.现在，让我们检查备用驱动器是否能自动工作，当我们阵列中的任何一个磁盘出现故障时。为了测试，我亲自将一个磁盘模拟为故障设备。
|
||||
|
||||
在这里，我们标记 /dev/sdd1 为故障磁盘。
|
||||
|
||||
# mdadm --manage --fail /dev/md0 /dev/sdd1
|
||||
|
||||
|
||||
|
||||
检查 Raid 6 容错
|
||||
|
||||
20.让我们查看 RAID 的详细信息，并检查备用磁盘是否开始同步。
|
||||
|
||||
# mdadm --detail /dev/md0
|
||||
|
||||
|
||||
|
||||
检查 Raid 自动同步
|
||||
|
||||
**哇塞!** 这里，我们看到备用磁盘激活了，并开始重建进程。在底部，我们可以看到有故障的磁盘 /dev/sdd1 标记为 faulty。可以使用下面的命令查看进程重建。
|
||||
|
||||
# cat /proc/mdstat
|
||||
|
||||
|
||||
|
||||
Raid 6 自动同步
|
||||
|
||||
### 结论: ###
|
||||
|
||||
在这里，我们看到了如何使用四个磁盘设置 RAID 6。这种 RAID 级别是具有高冗余的昂贵设置之一。在接下来的文章中，我们将看到如何建立一个嵌套的 RAID 10 甚至更多。至此，请继续关注 TECMINT。
|
||||
|
||||
--------------------------------------------------------------------------------
|
||||
|
||||
via: http://www.tecmint.com/create-raid-6-in-linux/
|
||||
|
||||
作者：[Babin Lonston][a]
|
||||
译者：[strugglingyouth](https://github.com/strugglingyouth)
|
||||
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/babinlonston/
|
||||
[1]:http://www.tecmint.com/understanding-raid-setup-in-linux/
|
||||
[2]:http://www.tecmint.com/create-raid0-in-linux/
|
||||
[3]:http://www.tecmint.com/create-raid1-in-linux/
|
||||
Loading…
Reference in New Issue
Block a user