diff --git a/sources/tech/20140714 Test read or write speed of usb and ssd drives with dd command on Linux.md b/sources/tech/20140714 Test read or write speed of usb and ssd drives with dd command on Linux.md deleted file mode 100644 index 6eb0617afa..0000000000 --- a/sources/tech/20140714 Test read or write speed of usb and ssd drives with dd command on Linux.md +++ /dev/null @@ -1,140 +0,0 @@ -(translated by runningwater) -Test read/write speed of usb and ssd drives with dd command on Linux -================================================================================ -### Drive speed ### - -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. - -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. - -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. - -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. - -### Test Method ### - -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. - -The general syntax of the dd command looks like this - - dd if=path/to/input_file of=/path/to/output_file bs=block_size count=number_of_blocks - -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. - -### SSD ### - -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. - -In this test the ssd is connected to a sata 2.0 port. - -#### Write speed #### - -Lets first write to the ssd - - $ dd if=/dev/zero of=./largefile bs=1M count=1024 - 1024+0 records in - 1024+0 records out - 1073741824 bytes (1.1 GB) copied, 4.82364 s, 223 MB/s - -Block size is actually quite large. You can try with smaller sizes like 64k or even 4k. - -#### Read speed #### - -Now read back the same file. However, first clear the memory cache to ensure that the file is actually read from drive. - -Run the following command to clear the memory cache - - $ sudo sh -c "sync && echo 3 > /proc/sys/vm/drop_caches" - -Now read the file - - $ dd if=./largefile of=/dev/null bs=4k - 165118+0 records in - 165118+0 records out - 676323328 bytes (676 MB) copied, 3.0114 s, 225 MB/s - -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. - -[https://wiki.archlinux.org/index.php/SSD_Benchmarking][1] - -### USB ### - -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. - -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. - -#### Sony 4GB - Write #### - -In this test, the dd command is used to write 10,000 chunks of 8 Kbyte each to a single file on the drive. - - # dd if=/dev/zero of=./largefile bs=8k count=10000 - 10000+0 records in - 10000+0 records out - 81920000 bytes (82 MB) copied, 11.0626 s, 7.4 MB/s - -So the write speed is around 7.5 MBytes/s. This is a low figure. - -#### Sony 4GB - Read #### - -The same file is read back to test the read speed. Run the following command to clear the memory cache - - $ sudo sh -c "sync && echo 3 > /proc/sys/vm/drop_caches" - -Now read the file using the dd command - - # dd if=./largefile of=/dev/null bs=8k - 8000+0 records in - 8000+0 records out - 65536000 bytes (66 MB) copied, 2.65218 s, 24.7 MB/s - -The read speed comes out around 25 Mbytes/s which is a more or less the standard for cheap usb drives. - -> 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. - -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 - -Now lets do the same test with a Strontium 16gb drive. Strontium is another very cheapy brand, although usb drives are reliable. - -#### Strontium 16gb write speed #### - - # dd if=/dev/zero of=./largefile bs=64k count=1000 - 1000+0 records in - 1000+0 records out - 65536000 bytes (66 MB) copied, 8.3834 s, 7.8 MB/s - -Strontium 16gb read speed - - # sudo sh -c "sync && echo 3 > /proc/sys/vm/drop_caches" - - # dd if=./largefile of=/dev/null bs=8k - 8000+0 records in - 8000+0 records out - 65536000 bytes (66 MB) copied, 2.90366 s, 22.6 MB/s - -The read speed is lower than the Sony drive. - -### Resources ### - -- [http://en.wikipedia.org/wiki/USB][2] -- [https://wiki.archlinux.org/index.php/SSD_Benchmarking][1] - ----------- - -![](http://0.gravatar.com/avatar/e23f2767e6907e798da5b28694a2bf28?s=64&d=&r=G) - -About Silver Moon - -Php developer, blogger and Linux enthusiast. He can be reached at [m00n.silv3r@gmail.com][e]. Or find him on [Google+][g] - --------------------------------------------------------------------------------- - -via: http://www.binarytides.com/linux-test-drive-speed/ - -译者：[runningwater](https://github.com/runningwater) 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](http://linux.cn/) 荣誉推出 - -[1]:http://wiki.archlinux.org/index.php/SSD_Benchmarking -[2]:http://en.wikipedia.org/wiki/USB -[e]:m00n.silv3r@gmail.com -[g]:http://plus.google.com/117145272367995638274/posts \ No newline at end of file diff --git a/translated/tech/20140714 Test read or write speed of usb and ssd drives with dd command on Linux.md b/translated/tech/20140714 Test read or write speed of usb and ssd drives with dd command on Linux.md new file mode 100644 index 0000000000..dc1b7c3101 --- /dev/null +++ b/translated/tech/20140714 Test read or write speed of usb and ssd drives with dd command on Linux.md @@ -0,0 +1,139 @@ +Linux系统中使用 DD 命令测试 USB 和 SSD 硬盘的读写速度 +================================================================================ +### 磁盘驱动器速度 ### + +磁盘驱动器的速度是以在一个单位时间内能读写数据量的多少来衡量的。DD 命令是一个简单的命令行工具，它可用对磁盘进行任意数据块的读取和写入，同时可以度量读取写入的速度。 + +在这篇文章中，我们将会使用 DD 命令来测试 USB 和 SSD 磁盘的读取和写入速度。 + +数据传输速度不但取决于驱动盘本身，而且还与连接的接口有关。比如， USB 2.0 端口的最大传输速度是 35 兆字节/秒，所以如果您把一个支持高速传输的 USB 3.0 驱动盘插入 USB 2.0 端口的话，它实际的传输速度将是 2.0 端口的上下限。 + +这对于 SSD 也是一样的。 SSD 连接的 SATA 端口有不同的类型。平均是 375 兆字节/秒的 SATA 2.0 端口理论上最大传输速度是 3 Gbit/秒，而 SATA 3.0 是这个速度的两倍。 + +### 测试方法 ### + +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。 + +DD 命令通用语法格式如下： + + dd if=path/to/input_file of=/path/to/output_file bs=block_size count=number_of_blocks + +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。 + +### 固态硬盘 ### + +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。 + +这次实验中，我们把硬盘接在 SATA 2.0 端口上。 + +#### 写入速度 #### + +首先让我们写入固态硬盘 + + $ dd if=/dev/zero of=./largefile bs=1M count=1024 + 1024+0 records in + 1024+0 records out + 1073741824 bytes (1.1 GB) copied, 4.82364 s, 223 MB/s + +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。 + +#### 读取速度 #### + +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。 + +运行下面的命令来清除内存缓存 + + $ sudo sh -c "sync && echo 3 > /proc/sys/vm/drop_caches" + +现在读取此文件 + + $ dd if=./largefile of=/dev/null bs=4k + 165118+0 records in + 165118+0 records out + 676323328 bytes (676 MB) copied, 3.0114 s, 225 MB/s + +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。 + +[https://wiki.archlinux.org/index.php/SSD_Benchmarking][1] + +### USB ### + +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。 + +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。 + +#### Sony 4GB - 写入 #### + +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。 + + # dd if=/dev/zero of=./largefile bs=8k count=10000 + 10000+0 records in + 10000+0 records out + 81920000 bytes (82 MB) copied, 11.0626 s, 7.4 MB/s + +因此，写入速度约为7.5兆字节/秒。这是一个很低的数字。 + +#### Sony 4GB - 读取 #### + +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 + + $ sudo sh -c "sync && echo 3 > /proc/sys/vm/drop_caches" + +现在就可以使用 DD 命令来读取文件了 + + # dd if=./largefile of=/dev/null bs=8k + 8000+0 records in + 8000+0 records out + 65536000 bytes (66 MB) copied, 2.65218 s, 24.7 MB/s + +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。 + +> 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。 + +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。 + +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。 + +#### Strontium 16gb 盘写入速度 #### + + # dd if=/dev/zero of=./largefile bs=64k count=1000 + 1000+0 records in + 1000+0 records out + 65536000 bytes (66 MB) copied, 8.3834 s, 7.8 MB/s + +#### Strontium 16gb 盘读取速度 #### + + # sudo sh -c "sync && echo 3 > /proc/sys/vm/drop_caches" + + # dd if=./largefile of=/dev/null bs=8k + 8000+0 records in + 8000+0 records out + 65536000 bytes (66 MB) copied, 2.90366 s, 22.6 MB/s + +它的读取速度就要比 Sony 的低了。 + +### 参考资料 ### + +- [http://en.wikipedia.org/wiki/USB][2] +- [https://wiki.archlinux.org/index.php/SSD_Benchmarking][1] + +---------- + +![](http://0.gravatar.com/avatar/e23f2767e6907e798da5b28694a2bf28?s=64&d=&r=G) + +关于 Silver Moon + +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。 + +-------------------------------------------------------------------------------- + +via: http://www.binarytides.com/linux-test-drive-speed/ + +译者：[runningwater](https://github.com/runningwater) 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](http://linux.cn/) 荣誉推出 + +[1]:http://wiki.archlinux.org/index.php/SSD_Benchmarking +[2]:http://en.wikipedia.org/wiki/USB +[e]:m00n.silv3r@gmail.com +[g]:http://plus.google.com/117145272367995638274/posts \ No newline at end of file