Dieter wrote:
AMD64  FreeBSD 7.0  2 GiB main memory

My console says:

login: swap_pager: indefinite wait buffer: bufobj: 0, blkno: 22, size: 4096
swap_pager: indefinite wait buffer: bufobj: 0, blkno: 22, size: 4096
swap_pager: indefinite wait buffer: bufobj: 0, blkno: 22, size: 4096
swap_pager: indefinite wait buffer: bufobj: 0, blkno: 22, size: 4096

pstat -sk
Device          1K-blocks     Used    Avail Capacity
/dev/ad6s10       4590208       96  4590112     0%

Wow, using a whole 96K of swap.  I don't see any disk related
complaints in dmesg.

Is this something to worry about?
Yes, the system was *trying* to do swap I/O and timing out while doing so.

Kris

Whoops, I forgot to change the subject line after adding the k option
to pstat.  Without the k it said 0 used.  And this morning it occurs to
me that even if swap used was zero, it could have been trying to *start*
using swap.

Anyway... given this timeout explaination, I'm guessing that page/swap
has to compete with user processes for disk i/o, and thus probably
suffers from the same lack of fair i/o scheduling that user processes
suffer from.  E.g. one process doing disk i/o can lock out another
process for at least several minutes, probably indefinitely.  :-(

There is a timeout of (from memory) 60 seconds. I've not seen this timeout exceeded on properly functioning disk hardware (even heavily loaded), only on broken hardware/controllers, or on I/O devices that are intrinsically slow for some reason (USB stick, or swapping to a file).

Unless you're doing something truly unspeakable to that disk's load, I'd look at the hardware.

Kris
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