Interpreting FreeBSD 'vmstat' output

[Brian Candler <B.Candler at pobox.com>]

Hello,

I wonder if one of the deep kernel experts on this list can explain to me
how to interpret the output of 'vmstat' in FreeBSD.

I have a box here which has 1GB of RAM (running FreeBSD-4.5-RELEASE):

Mar 19 14:46:15 radius-b-lond /kernel: real memory  = 1073676288 (1048512K bytes)
Mar 19 14:46:15 radius-b-lond /kernel: avail memory = 1040379904 (1015996K bytes)

This is what 'vmstat' shows:

# vmstat 2
 procs      memory      page                    disks     faults      cpu
 r b w     avm    fre  flt  re  pi  po  fr  sr da0 da1   in   sy  cs us sy id
 0 0 0   27908  32100  129   0   0   0 121   2   0   0   54   92  39 -3 -1 104
 1 0 0   27908  32084  224   0   0   0 187   0   0   0  347 1018  90  7  2 91
 0 0 0   27908  32052    2   0   0   0  29   0   2   0  381  939  94  9  1 90
 0 0 0   28320  32036  223   0   0   0 198   0   3   0  365  987 109  7  2 92
 0 0 0   28320  32004  224   0   0   0 201   0   0   0  381 1207 108  8  3 89
 0 0 0   28320  31972    2   0   0   0  15   0   1   0  346  816  84  8  2 90
 1 0 0   28320  31940  224   0   0   0 201   0   0   0  394 1340 114 11  2 86
 0 0 0   28320  31908  224   0   0   0 201   0   1   0  388 1265 113 10  3 87

I'm not sure how to interpret the 'fre' column - surely there is more than
32MB of available RAM? And the number of page faults seems high, if 'page
fault' means 'event where I had to go to disk or swap to read a page' -
although the level of disk I/O is low.

'top' reports:

Mem: 29M Active, 800M Inact, 139M Wired, 33M Cache, 112M Buf, 3476K Free
Swap: 1024M Total, 40K Used, 1024M Free

This looks a bit more sensible. This machine is only running one main user
process (a radius daemon) with 'SIZE' and 'RES' both about 15MB. Yes, I
know that a 1GB machine is overkill for this application :-)

Also, what does 'Inact' and 'Wired' mean? What is the difference between
RAM in this state and RAM which is 'Free'?

Thanks...

Brian.

-----
This is the afnog mailing list, managed by Majordomo 1.94.5

To send a message to this list, e-mail afnog at afnog.org
To send a request to majordomo, e-mail majordomo at afnog.org and put
your request in the body of the message (i.e use "help" for help)

This list is maintained by owner-afnog at afnog.org