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(translated by runningwater)
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Test read/write speed of usb and ssd drives with dd command on Linux
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================================================================================
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### Drive speed ###
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The speed of a drive is measured in terms of how much data it can read or write in unit time. The dd command is a simple command line tool that can be used to read and write arbitrary blocks of data to a drive and measure the speed at which the data transfer took place.
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In this post we shall use the dd command to test and read and write speed of usb and ssd drives using the dd command.
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The data transfer speed does not depend solely on the drive, but also on the interface it is connected to. For example a usb 2.0 port has a maximum operational speed limit of 35 Mbytes/s, so even if you were to plug a high speed usb 3 pen drive into a usb 2 port, the speed would be capped to the lower limit.
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The same applies to SSD. SSD connect via SATA ports which have different versions. Sata 2.0 has a maximum theoretical speed limit of 3Gbits/s which is roughly 375 Mbytes/s. Whereas Sata 3.0 supports twice that speed.
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### Test Method ###
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Mount the drive and navigate into it from the terminal. Then use the dd command to first write a file using fixed sized blocks. Then read the same file out using the same block site.
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The general syntax of the dd command looks like this
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dd if=path/to/input_file of=/path/to/output_file bs=block_size count=number_of_blocks
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When writing to the drive, we simply read from /dev/zero which is a source of infinite useless bytes. And when read from the drive, we read the file written earlier and send it to /dev/null which is nowhere. In the whole process, dd keeps track of the speed with which the transfer takes place and reports it.
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### SSD ###
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The SSD that we are using is a "Samsung Evo 120GB" ssd. It is a beginner level ssd that comes within a decent budget and is also my first SSD. It is also one of the best performing ssds, in the market.
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In this test the ssd is connected to a sata 2.0 port.
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#### Write speed ####
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Lets first write to the ssd
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$ dd if=/dev/zero of=./largefile bs=1M count=1024
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1024+0 records in
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1024+0 records out
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1073741824 bytes (1.1 GB) copied, 4.82364 s, 223 MB/s
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Block size is actually quite large. You can try with smaller sizes like 64k or even 4k.
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#### Read speed ####
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Now read back the same file. However, first clear the memory cache to ensure that the file is actually read from drive.
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Run the following command to clear the memory cache
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$ sudo sh -c "sync && echo 3 > /proc/sys/vm/drop_caches"
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Now read the file
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$ dd if=./largefile of=/dev/null bs=4k
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165118+0 records in
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165118+0 records out
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676323328 bytes (676 MB) copied, 3.0114 s, 225 MB/s
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The Arch Linux wiki has a page full of information about the read/write speed of various SSDs from different vendors like Intel, Samsung, Sandisk etc. Check it out at the following url.
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[https://wiki.archlinux.org/index.php/SSD_Benchmarking][1]
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### USB ###
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In this test we shall measure the read and write speed of ordinary usb/pen drives. The drives are plugged to standard usb 2 ports. The first one is a sony 4gb usb drive and the second is a strontium 16gb drive.
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First plug the drive into the port and mount it, so that it is readable. Then navigate into the mount directory from the command line.
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#### Sony 4GB - Write ####
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In this test, the dd command is used to write 10,000 chunks of 8 Kbyte each to a single file on the drive.
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# dd if=/dev/zero of=./largefile bs=8k count=10000
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10000+0 records in
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10000+0 records out
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81920000 bytes (82 MB) copied, 11.0626 s, 7.4 MB/s
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So the write speed is around 7.5 MBytes/s. This is a low figure.
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#### Sony 4GB - Read ####
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The same file is read back to test the read speed. Run the following command to clear the memory cache
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$ sudo sh -c "sync && echo 3 > /proc/sys/vm/drop_caches"
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Now read the file using the dd command
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# dd if=./largefile of=/dev/null bs=8k
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8000+0 records in
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8000+0 records out
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65536000 bytes (66 MB) copied, 2.65218 s, 24.7 MB/s
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The read speed comes out around 25 Mbytes/s which is a more or less the standard for cheap usb drives.
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> USB 2.0 has a theoretical maximum signaling rate of 480 Mbits/s or 60 Mbytes/s. However due to various constraints the maximum throughput is restricted to around 280 Mbit/s or 35 Mbytes/s. Beyond this the actual speed achieved depends on the quality of the pen drives and other factors too.
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And the above usb drive was plugged inside a USB 2.0 port and it achieved a read speed of 24.7 Mbytes/s which is not very bad. But the write speed lags much behind
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Now lets do the same test with a Strontium 16gb drive. Strontium is another very cheapy brand, although usb drives are reliable.
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#### Strontium 16gb write speed ####
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# dd if=/dev/zero of=./largefile bs=64k count=1000
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1000+0 records in
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1000+0 records out
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65536000 bytes (66 MB) copied, 8.3834 s, 7.8 MB/s
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Strontium 16gb read speed
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# sudo sh -c "sync && echo 3 > /proc/sys/vm/drop_caches"
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# dd if=./largefile of=/dev/null bs=8k
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8000+0 records in
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8000+0 records out
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65536000 bytes (66 MB) copied, 2.90366 s, 22.6 MB/s
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The read speed is lower than the Sony drive.
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### Resources ###
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- [http://en.wikipedia.org/wiki/USB][2]
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- [https://wiki.archlinux.org/index.php/SSD_Benchmarking][1]
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----------
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About Silver Moon
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Php developer, blogger and Linux enthusiast. He can be reached at [m00n.silv3r@gmail.com][e]. Or find him on [Google+][g]
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--------------------------------------------------------------------------------
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via: http://www.binarytides.com/linux-test-drive-speed/
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译者：[runningwater](https://github.com/runningwater) 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](http://linux.cn/) 荣誉推出
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[1]:http://wiki.archlinux.org/index.php/SSD_Benchmarking
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[2]:http://en.wikipedia.org/wiki/USB
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[e]:m00n.silv3r@gmail.com
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[g]:http://plus.google.com/117145272367995638274/posts
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@ -12,96 +12,96 @@ Linux系统中使用 DD 命令测试 USB 和 SSD 硬盘的读写速度
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### 测试方法 ###
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Mount the drive and navigate into it from the terminal. Then use the dd command to first write a file using fixed sized blocks. Then read the same file out using the same block site.
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挂载上驱动盘，终端上进入此盘目录下。然后使用 DD 命令，首先写入固定大小块的一个文件，接着读取这个文件。
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The general syntax of the dd command looks like this
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DD 命令通用语法格式如下：
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dd if=path/to/input_file of=/path/to/output_file bs=block_size count=number_of_blocks
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When writing to the drive, we simply read from /dev/zero which is a source of infinite useless bytes. And when read from the drive, we read the file written earlier and send it to /dev/null which is nowhere. In the whole process, dd keeps track of the speed with which the transfer takes place and reports it.
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当写入到驱动盘的时候，我们简单的从无穷无用字节的源 /dev/zero 读取，当从驱动盘读取的时候，我们读取的是刚才的文件，并把输出结果发送到无用的 /dev/null。在整个操作过程中， DD 命令会跟踪数据传输的速度并且报告出结果。
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### SSD ###
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### 固态硬盘 ###
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The SSD that we are using is a "Samsung Evo 120GB" ssd. It is a beginner level ssd that comes within a decent budget and is also my first SSD. It is also one of the best performing ssds, in the market.
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我们使用的是一块“三星 Evo 120G” 的固态硬盘。它性价比很高，很适合刚开始用固态硬盘的用户，也是我的第一块固态硬盘，并且在市场上表现的也非常不错。
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In this test the ssd is connected to a sata 2.0 port.
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这次实验中，我们把硬盘接在 SATA 2.0 端口上。
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#### Write speed ####
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#### 写入速度 ####
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Lets first write to the ssd
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首先让我们写入固态硬盘
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$ dd if=/dev/zero of=./largefile bs=1M count=1024
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1024+0 records in
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1024+0 records out
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1073741824 bytes (1.1 GB) copied, 4.82364 s, 223 MB/s
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Block size is actually quite large. You can try with smaller sizes like 64k or even 4k.
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的大小实际上是相当大的。你可以尝试用更小的尺寸如 64 K甚至是 4K 的。
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#### Read speed ####
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#### 读取速度 ####
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Now read back the same file. However, first clear the memory cache to ensure that the file is actually read from drive.
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现在读回这个文件。但是，得首先清除内存的缓存，以确保这个文件确实是从驱动盘读取的。
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Run the following command to clear the memory cache
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运行下面的命令来清除内存缓存
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$ sudo sh -c "sync && echo 3 > /proc/sys/vm/drop_caches"
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Now read the file
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现在读取此文件
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$ dd if=./largefile of=/dev/null bs=4k
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165118+0 records in
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165118+0 records out
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676323328 bytes (676 MB) copied, 3.0114 s, 225 MB/s
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The Arch Linux wiki has a page full of information about the read/write speed of various SSDs from different vendors like Intel, Samsung, Sandisk etc. Check it out at the following url.
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在 Arch Linux 的维基页上有一整页的关于从同的厂商，如英特尔、三星、Sandisk 等提供的各类固态硬盘的读/写速度的信息。点击如下的 url 可得到得到想着信息。
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[https://wiki.archlinux.org/index.php/SSD_Benchmarking][1]
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### USB ###
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In this test we shall measure the read and write speed of ordinary usb/pen drives. The drives are plugged to standard usb 2 ports. The first one is a sony 4gb usb drive and the second is a strontium 16gb drive.
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此次实验我们会测量普通的 USB/随身笔的读写速度。驱动盘都是接入标准的 USB 2.0 端口的。首先用的是一个 4GB 大小的 sony USB 驱动盘，随后用的是一个 16GB 大小的 strontium 驱动盘。
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First plug the drive into the port and mount it, so that it is readable. Then navigate into the mount directory from the command line.
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首先把驱动盘插入端口，并挂载上，使其可读的。然后从命令行下面进入挂载的文件目录下。
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#### Sony 4GB - Write ####
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#### Sony 4GB - 写入 ####
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In this test, the dd command is used to write 10,000 chunks of 8 Kbyte each to a single file on the drive.
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这个实验中，用 DD 命令向驱动盘写入一个有 10000 块，每块 8K 字节的文件。
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# dd if=/dev/zero of=./largefile bs=8k count=10000
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10000+0 records in
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10000+0 records out
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81920000 bytes (82 MB) copied, 11.0626 s, 7.4 MB/s
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So the write speed is around 7.5 MBytes/s. This is a low figure.
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因此，写入速度约为7.5兆字节/秒。这是一个很低的数字。
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#### Sony 4GB - Read ####
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#### Sony 4GB - 读取 ####
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The same file is read back to test the read speed. Run the following command to clear the memory cache
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把相同的文件读取回来，测试速度。首先运行如下命令清除内存缓存
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$ sudo sh -c "sync && echo 3 > /proc/sys/vm/drop_caches"
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Now read the file using the dd command
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现在就可以使用 DD 命令来读取文件了
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# dd if=./largefile of=/dev/null bs=8k
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8000+0 records in
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8000+0 records out
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65536000 bytes (66 MB) copied, 2.65218 s, 24.7 MB/s
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The read speed comes out around 25 Mbytes/s which is a more or less the standard for cheap usb drives.
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读取速度出来大约是25兆字节/秒，这大致跟廉价 USB 驱动盘的标准相匹配吧。
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> USB 2.0 has a theoretical maximum signaling rate of 480 Mbits/s or 60 Mbytes/s. However due to various constraints the maximum throughput is restricted to around 280 Mbit/s or 35 Mbytes/s. Beyond this the actual speed achieved depends on the quality of the pen drives and other factors too.
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> USB2.0 理论上最大信号传输速率为480兆比特/秒，最小为60兆字节/秒。然而，由于各种限制实际传输速率大约280兆比特/秒和35兆字节/秒之间。除了这个，实际的速度还取决于驱动盘本身的质量好坏以及其他的因素。
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And the above usb drive was plugged inside a USB 2.0 port and it achieved a read speed of 24.7 Mbytes/s which is not very bad. But the write speed lags much behind
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上面实验中， USB 驱动盘插入USB 2.0 端口，读取的速度达到了 24.7兆字节/秒，这是很不错的读速度。但写入速度就不敢恭维了。
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Now lets do the same test with a Strontium 16gb drive. Strontium is another very cheapy brand, although usb drives are reliable.
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下面让我们用 Strontium 的 16GB 的驱动盘来做相同的实验。虽然 Strontium 的 USB 驱动盘很稳定，但它也是一款很便宜的品牌。
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#### Strontium 16gb write speed ####
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#### Strontium 16gb 盘写入速度 ####
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# dd if=/dev/zero of=./largefile bs=64k count=1000
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1000+0 records in
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1000+0 records out
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65536000 bytes (66 MB) copied, 8.3834 s, 7.8 MB/s
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Strontium 16gb read speed
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#### Strontium 16gb 盘读取速度 ####
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# sudo sh -c "sync && echo 3 > /proc/sys/vm/drop_caches"
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@ -110,9 +110,9 @@ Strontium 16gb read speed
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8000+0 records out
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65536000 bytes (66 MB) copied, 2.90366 s, 22.6 MB/s
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The read speed is lower than the Sony drive.
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它的读取速度就要比 Sony 的低了。
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### Resources ###
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### 参考资料 ###
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- [http://en.wikipedia.org/wiki/USB][2]
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- [https://wiki.archlinux.org/index.php/SSD_Benchmarking][1]
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@ -121,9 +121,9 @@ The read speed is lower than the Sony drive.
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About Silver Moon
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关于 Silver Moon
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Php developer, blogger and Linux enthusiast. He can be reached at [m00n.silv3r@gmail.com][e]. Or find him on [Google+][g]
|
||||
Php 开发者, 博主 和 Linux 爱好者. 通过 [m00n.silv3r@gmail.com][e] 或者 [Google+][g] 可联系到他。
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--------------------------------------------------------------------------------
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