{"id":6995,"date":"2018-10-10T19:36:32","date_gmt":"2018-10-10T16:36:32","guid":{"rendered":"https:\/\/www.howtoforge.com\/linux-vmstat-command\/"},"modified":"2018-10-10T19:36:32","modified_gmt":"2018-10-10T16:36:32","slug":"linux-vmstat-command-tutorial-for-beginners-5-examples","status":"publish","type":"post","link":"https:\/\/afaghhosting.net\/blog\/linux-vmstat-command-tutorial-for-beginners-5-examples\/","title":{"rendered":"Linux vmstat Command Tutorial for Beginners (5 Examples)"},"content":{"rendered":"

If you are looking for a command line utility that you can use to access information about processes, CPU activity, memory, and more, you’ll be glad to know that vmstat<\/strong> does this for you.<\/p>\n

In this article, we will discuss basics of this tool using some easy to understand examples. But before we do that, it’s worth mentioning that all examples in this article have been tested on an Ubuntu 18.04 LTS machine.<\/p>\n

Linux vmstat command<\/h2>\n

The vmstat command in Linux reports virtual memory statistics. Following is its syntax:<\/p>\n

vmstat [options] [delay [count]]<\/p>\n

And here’s how the tool’s man page explains it:<\/p>\n

 vmstat\u00a0 reports\u00a0 information about processes, memory, paging, block IO,\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 traps, disks and cpu activity.
\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 The first report produced gives averages since the last reboot.\u00a0\u00a0 Addi?\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 tional\u00a0 reports\u00a0 give information on a sampling period of length delay.\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 The process and memory reports are instantaneous in either case.<\/p><\/pre>\n
Following are some Q&A-styled examples that should give you a better idea on how the vmstat command works:<\/p>\n
Q1. How to use vmstat?<\/h2>\n
For basic usage, just execute ‘vmstat’ sans any option.<\/p>\n
vmstat<\/p>\n
For example, in my case, the above command produced the following output:<\/p>\n
procs -----------memory---------- ---swap-- -----io---- -system-- ------cpu-----\u00a0r\u00a0 b\u00a0\u00a0 swpd\u00a0\u00a0 free\u00a0\u00a0 buff\u00a0 cache\u00a0\u00a0 si\u00a0\u00a0 so\u00a0\u00a0\u00a0 bi\u00a0\u00a0\u00a0 bo\u00a0\u00a0 in\u00a0\u00a0 cs us sy id wa st\u00a02\u00a0 0 805624 770924\u00a0 41792 838568\u00a0\u00a0\u00a0 2\u00a0\u00a0 10\u00a0\u00a0\u00a0 35\u00a0\u00a0\u00a0 57\u00a0 392\u00a0 225 10\u00a0 2 86\u00a0 1\u00a0 0<\/pre>\n
As the first row indicates, the output is divided into six sections. The tool’s man page contains detailed information about these values. Here’s the excerpt:<\/p>\n
Procs\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 r: The number of runnable processes (running or waiting for run time).\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 b: The number of processes in uninterruptible sleep.
\u00a0\u00a0 Memory\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 swpd: the amount of virtual memory used.\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 free: the amount of idle memory.\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 buff: the amount of memory used as buffers.\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 cache: the amount of memory used as cache.\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 inact: the amount of inactive memory.\u00a0 (-a option)\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 active: the amount of active memory.\u00a0 (-a option)<\/p>
\u00a0\u00a0 Swap\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 si: Amount of memory swapped in from disk (\/s).\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 so: Amount of memory swapped to disk (\/s).<\/p>
\u00a0\u00a0 IO\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 bi: Blocks received from a block device (blocks\/s).\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 bo: Blocks sent to a block device (blocks\/s).<\/p>
\u00a0\u00a0 System\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 in: The number of interrupts per second, including the clock.\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 cs: The number of context switches per second.<\/p>
\u00a0\u00a0 CPU\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 These are percentages of total CPU time.\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 us: Time spent running non-kernel code.\u00a0 (user time, including nice time)\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 sy: Time spent running kernel code.\u00a0 (system time)\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 id: Time spent idle.\u00a0 Prior to Linux 2.5.41, this includes IO-wait time.\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 wa: Time spent waiting for IO.\u00a0 Prior to Linux 2.5.41, included in idle.\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 st: Time stolen from a virtual machine.\u00a0 Prior to Linux 2.6.11, unknown.<\/p><\/pre>\n
Q2. How to make vmstat auto update its output?<\/h2>\n
By default, vmstat produces output once. However, if you want vmstat to automatically update its output, then you can do that by specifying a numeric value as input to the command.<\/p>\n
This numeric value acts as delay (in seconds) after which the output is updated. For example:<\/p>\n
vmstat 3<\/p>\n
This way, vmstat output will get refreshed every 3 seconds.<\/p>\n
procs -----------memory---------- ---swap-- -----io---- -system-- ------cpu-----\u00a0r\u00a0 b\u00a0\u00a0 swpd\u00a0\u00a0 free\u00a0\u00a0 buff\u00a0 cache\u00a0\u00a0 si\u00a0\u00a0 so\u00a0\u00a0\u00a0 bi\u00a0\u00a0\u00a0 bo\u00a0\u00a0 in\u00a0\u00a0 cs us sy id wa st\u00a01\u00a0 0 824320 1067960\u00a0 20500 507612\u00a0\u00a0\u00a0 2\u00a0\u00a0 10\u00a0\u00a0\u00a0 36\u00a0\u00a0\u00a0 56\u00a0 412\u00a0 296 11\u00a0 2 86\u00a0 1\u00a0 0\u00a00\u00a0 0 824320 1068116\u00a0 20532 507176\u00a0\u00a0\u00a0 0\u00a0\u00a0\u00a0 0\u00a0\u00a0\u00a0\u00a0 0\u00a0\u00a0\u00a0 39 2648 6093\u00a0 4\u00a0 1 93\u00a0 1\u00a0 0\u00a00\u00a0 0 824320 1062420\u00a0 20548 507160\u00a0\u00a0\u00a0 0\u00a0\u00a0\u00a0 0\u00a0\u00a0\u00a0\u00a0 0\u00a0\u00a0\u00a0 48 2603 5895\u00a0 5\u00a0 1 93\u00a0 1\u00a0 0\u00a00\u00a0 0 824320 1060180\u00a0 20556 507152\u00a0\u00a0\u00a0 0\u00a0\u00a0\u00a0 0\u00a0\u00a0\u00a0\u00a0 0\u00a0\u00a0 289 2815 6092\u00a0 4\u00a0 1 94\u00a0 0\u00a0 0\u00a01\u00a0 0 824320 1059940\u00a0 20580 509216\u00a0\u00a0\u00a0 0\u00a0\u00a0\u00a0 0\u00a0\u00a0\u00a0\u00a0 0\u00a0\u00a0\u00a0 31 2578 5937\u00a0 5\u00a0 1 93\u00a0 1\u00a0 0.........<\/pre>\n
Q3. How to make vmstat display slabinfo?<\/h2>\n
For slabinfo, you need to use the -m command line option. Note that your Linux distribution’s kernel needs to support slabinfo for this option to work. If support is there, then you need to run the command with\u00a0sudo<\/a> permissions.<\/p>\n
sudo vmstat -m<\/p>\n
For example, in my case, here’s an excerpt of the output produced:<\/p>\n
Cache\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 Num\u00a0 Total\u00a0\u00a0 Size\u00a0 Pagesext4_groupinfo_4k\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 1568\u00a0\u00a0 1568\u00a0\u00a0\u00a0 144\u00a0\u00a0\u00a0\u00a0 28drm_i915_gem_request\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 112\u00a0\u00a0\u00a0 112\u00a0\u00a0\u00a0 576\u00a0\u00a0\u00a0\u00a0 28i915_vma\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 934\u00a0\u00a0 1012\u00a0\u00a0\u00a0 704\u00a0\u00a0\u00a0\u00a0 23drm_i915_gem_object\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 896\u00a0\u00a0 1050\u00a0\u00a0\u00a0 768\u00a0\u00a0\u00a0\u00a0 21RAWv6\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 140\u00a0\u00a0\u00a0 140\u00a0\u00a0 1152\u00a0\u00a0\u00a0\u00a0 28UDPv6\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 104\u00a0\u00a0\u00a0 104\u00a0\u00a0 1216\u00a0\u00a0\u00a0\u00a0 26tw_sock_TCPv6\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 17\u00a0\u00a0\u00a0\u00a0 17\u00a0\u00a0\u00a0 240\u00a0\u00a0\u00a0\u00a0 17request_sock_TCPv6\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 0\u00a0\u00a0\u00a0\u00a0\u00a0 0\u00a0\u00a0\u00a0 304\u00a0\u00a0\u00a0\u00a0 26TCPv6\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 60\u00a0\u00a0\u00a0\u00a0 60\u00a0\u00a0 2176\u00a0\u00a0\u00a0\u00a0 15kcopyd_job\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 0\u00a0\u00a0\u00a0\u00a0\u00a0 0\u00a0\u00a0 3312\u00a0\u00a0\u00a0\u00a0\u00a0 9dm_uevent\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 0\u00a0\u00a0\u00a0\u00a0\u00a0 0\u00a0\u00a0 2632\u00a0\u00a0\u00a0\u00a0 12cfq_io_cq\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 442\u00a0\u00a0\u00a0 442\u00a0\u00a0\u00a0 120\u00a0\u00a0\u00a0\u00a0 34cfq_queue\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 408\u00a0\u00a0\u00a0 408\u00a0\u00a0\u00a0 240\u00a0\u00a0\u00a0\u00a0 17bsg_cmd\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 0\u00a0\u00a0\u00a0\u00a0\u00a0 0\u00a0\u00a0\u00a0 216\u00a0\u00a0\u00a0\u00a0 18mqueue_inode_cache\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 68\u00a0\u00a0\u00a0\u00a0 68\u00a0\u00a0\u00a0 960\u00a0\u00a0\u00a0\u00a0 17fuse_request\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 40\u00a0\u00a0\u00a0\u00a0 40\u00a0\u00a0\u00a0 400\u00a0\u00a0\u00a0\u00a0 20fuse_inode\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 19\u00a0\u00a0\u00a0\u00a0 19\u00a0\u00a0\u00a0 832\u00a0\u00a0\u00a0\u00a0 19ecryptfs_inode_cache\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 0\u00a0\u00a0\u00a0\u00a0\u00a0 0\u00a0\u00a0 1024\u00a0\u00a0\u00a0\u00a0 16.........<\/pre>\n
Q4. How to make vmstat report disk activity summary stats?<\/h2>\n
Use the -D command line option for it.<\/p>\n
vmstat -D<\/p>\n
Here’s the output this command produced on my system:<\/p>\n
 21 disks \u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 8 partitions \u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 158637 total reads\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 31589 merged reads\u00a0\u00a0\u00a0\u00a0\u00a0 7376734 read sectors\u00a0\u00a0\u00a0\u00a0\u00a0 2099724 milli reading\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 198763 writes\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 553378 merged writes\u00a0\u00a0\u00a0\u00a0 11743120 written sectors\u00a0\u00a0\u00a0\u00a0\u00a0 6396664 milli writing\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 0 inprogress IO\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 1248 milli spent IO<\/pre>\n
Q5. How to make vmstat append timestamp to each output line?<\/h2>\n
To make sure the vmstat command appends timestamp to each output line, use the -t command line:<\/p>\n
vmstat -t<\/p>\n
$ vmstat 2 -tprocs -----------memory---------- ---swap-- -----io---- -system-- ------cpu----- -----timestamp-----\u00a0r\u00a0 b\u00a0\u00a0 swpd\u00a0\u00a0 free\u00a0\u00a0 buff\u00a0 cache\u00a0\u00a0 si\u00a0\u00a0 so\u00a0\u00a0\u00a0 bi\u00a0\u00a0\u00a0 bo\u00a0\u00a0 in\u00a0\u00a0 cs us sy id wa st\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 IST<\/strong>\u00a01\u00a0 0 822528 855556\u00a0 36820 689220\u00a0\u00a0\u00a0 1\u00a0\u00a0\u00a0 9\u00a0\u00a0\u00a0 34\u00a0\u00a0\u00a0 54\u00a0\u00a0 62\u00a0\u00a0 68 11\u00a0 2 86\u00a0 1\u00a0 0 2018-09-27 16:29:40<\/strong>\u00a00\u00a0 0 822528 849612\u00a0 36828 692792\u00a0\u00a0\u00a0 0\u00a0\u00a0\u00a0 0\u00a0\u00a0\u00a0\u00a0 0\u00a0\u00a0\u00a0 30 2894 7141\u00a0 7\u00a0 2 91\u00a0 1\u00a0 0 2018-09-27 16:29:42<\/strong>\u00a01\u00a0 0 822528 851820\u00a0 36856 697288\u00a0\u00a0\u00a0 0\u00a0\u00a0\u00a0 0\u00a0\u00a0\u00a0\u00a0 0\u00a0\u00a0 276 3081 7072 17\u00a0 2 80\u00a0 1\u00a0 0 2018-09-27 16:29:44<\/strong>\u00a00\u00a0 0 822528 850968\u00a0 36856 697420\u00a0\u00a0\u00a0 0\u00a0\u00a0\u00a0 0\u00a0\u00a0\u00a0\u00a0 0\u00a0\u00a0\u00a0\u00a0 0 3025 8067\u00a0 7\u00a0 2 91\u00a0 0\u00a0 0 2018-09-27 16:29:46<\/strong>\u00a00\u00a0 0 822528 853480\u00a0 36856 693360\u00a0\u00a0\u00a0 0\u00a0\u00a0\u00a0 0\u00a0\u00a0\u00a0\u00a0 0\u00a0\u00a0\u00a0\u00a0 0 2762 6285\u00a0 5\u00a0 1 93\u00a0 0\u00a0 0 2018-09-27 16:29:48<\/strong>\u00a00\u00a0 0 822528 853128\u00a0 36872 692796\u00a0\u00a0\u00a0 0\u00a0\u00a0\u00a0 0\u00a0\u00a0\u00a0\u00a0 0\u00a0\u00a0 140 2881 6534\u00a0 6\u00a0 1 91\u00a0 2\u00a0 0 2018-09-27 16:29:50<\/strong>\u00a00\u00a0 0 822528 846924\u00a0 36872 697108\u00a0\u00a0\u00a0 0\u00a0\u00a0\u00a0 0\u00a0\u00a0\u00a0\u00a0 0\u00a0\u00a0\u00a0\u00a0 0 2843 6637\u00a0 6\u00a0 2 93\u00a0 0\u00a0 0 2018-09-27 16:29:52<\/strong><\/pre>\n
The highlighted entries show the timestamp included in each line.<\/p>\n
Conclusion<\/h2>\n
Depending on the kind of work you do on the Linux command line, the vmstat command can prove to be really helpful. Apart from the options discussed here, there are a lot of other command line options that this tool offers. Head\u00a0here<\/a> to learn more.<\/p>\n
\n\"Himanshu <\/p>\n
About Himanshu Arora<\/strong><\/p>\n
Himanshu Arora has been working on Linux since 2007. He carries professional experience in system level programming, networking protocols, and command line. In addition to HowtoForge, Himanshu’s work has also been featured in some of world’s other leading publications including Computerworld, IBM DeveloperWorks, and Linux Journal.<\/p>\n<\/div>\n
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If you are looking for a command line utility that you can use to access information about processes, CPU activity, memory, and more, you’ll be glad to know that vmstat does this for you. In this article, we will discuss basics of this tool using some easy to understand examples. But before we do that, […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[36],"tags":[],"class_list":["post-6995","post","type-post","status-publish","format-standard","hentry","category-36"],"_links":{"self":[{"href":"https:\/\/afaghhosting.net\/blog\/wp-json\/wp\/v2\/posts\/6995","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/afaghhosting.net\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/afaghhosting.net\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/afaghhosting.net\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/afaghhosting.net\/blog\/wp-json\/wp\/v2\/comments?post=6995"}],"version-history":[{"count":0,"href":"https:\/\/afaghhosting.net\/blog\/wp-json\/wp\/v2\/posts\/6995\/revisions"}],"wp:attachment":[{"href":"https:\/\/afaghhosting.net\/blog\/wp-json\/wp\/v2\/media?parent=6995"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/afaghhosting.net\/blog\/wp-json\/wp\/v2\/categories?post=6995"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/afaghhosting.net\/blog\/wp-json\/wp\/v2\/tags?post=6995"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}