topic Re: vmstat (al,os ......) in Operating System - Linux

vmstat (al,os ......)

jousif — Sun, 26 Mar 2006 07:47:49 GMT

Hi admins,
how can I undersatand what is (al , os ...)
mean from the vmstat command .
else the man vmstat,
please advise I want to know how the system memory is used,
many thanks.

Re: vmstat (al,os ......)

Steven E. Protter — Sun, 26 Mar 2006 14:51:48 GMT

Shalom jousif,

vmstat measures use of virtual memory.

Virtual memory is disk that is used to swap processes from memory to disk when there is more need for memory than memory.

With memory prices low, the ideal system never actually pages to disk using vm, it reserves memory for swap but never uses it.

SEP

Re: vmstat (al,os ......)

Stuart Browne — Sun, 26 Mar 2006 21:31:04 GMT

Actually, 'vmstat' shows the current memory usage, as well as the virtual memory usage, as well as some basic disk-io, and system process stats.

Typical output of vmstat:

procs -----------memory---------- ---swap-- -----io---- --system-- ----cpu----
r b swpd free inact active si so bi bo in cs us sy id wa
1 0 604916 115680 62476 278680 6 4 2 2 1 1 24 9 62 5

of

procs -----------memory---------- ---swap-- -----io---- --system-- ----cpu----
r b swpd free buff cache si so bi bo in cs us sy id wa
1 33 624408 7508 5220 27916 6 4 2 2 1 1 24 9 62 5

(this will look screwey, damn lack of fixed-width fonts!).

These are all detailed in the man page.

I use this output with MRTG to map current memory usage.

Other ways to get the current memory usage are to use 'free', or to directly 'cat /proc/meminfo'. All of these tools look at that for their details anyway.

'free' (which is basically the same as the top section of the 'top' command) shows things the clearest.

Total memory. Free memory. Total swap. Free swap.

Be aware that the Buffers and Cache values are automatically assigned, and change regularly. If you have a system that is using lots of swap, and the Buffers and Cache values aren't that big, then definately get more memory.

Re: vmstat (al,os ......)

Muthukumar_5 — Mon, 27 Mar 2006 01:37:17 GMT

Use this,

http://www.tech-recipes.com/solaris_system_administration_tips165.html

to interpret output.

--
Muthu

Re: vmstat (al,os ......)

jousif — Mon, 27 Mar 2006 01:39:21 GMT

many thanks to browne & protter
I mean when I issue the command
% vmstat -P
the output what means ( al,os ...)
thanks.