How to solve mysterious system lockups?

[Tek Bahadur Limbu]

Nicole Harrington wrote:
> Hello
>   I have several systems that are used as squid
> caching servers. I have some systems that use SCSI
> disks and some  that use SATA disks. They are
> identical in everyway except for the sata vs SCSI
> drives. 
> 
>  At random times, the sata based systems seem to be
> freezing. You can ping them and they respond, but you
> cannot log in. Nor are any logs processed during that
> time. 
> 
>  I figure it mist be something to do with the disks,
> but I am not sure how to solve it. There seems to be
> little rhyme or reason. It does not happen necessarily
> during busy times. It can happen in the middle of the
> night.
> 
>  Any pointers in how to track down the cause would be
> much appreciated.
> 
>  Tyan S2881 Motherboard - 4gigs mem
>  Using 4 SATA (or scsi) drives
>  FreeBSD 6.2-STABLE.

Hi Nicole,

I had once experienced the same problem of system lockups in my 
FreeBSD-6.x servers running Squid. Most of them used SATA disks.

I could ping the servers but could not SSH into them. It seemed as tcp 
connections had stopped in the servers.

However, my problem was caused by high mbufs usage. What do you get from 
the following commands?

netstat -mb
sysctl kern.ipc.nmbclusters

Try increasing your mbufs if in case they are too low.

But your problem might not be related to mbufs and sockets.

Thanking you...


> 
>  Thanks!
> 
>   Nicole
> 
> 
> _______________________________________________
> freebsd-questions at freebsd.org mailing list
> http://lists.freebsd.org/mailman/listinfo/freebsd-questions
> To unsubscribe, send any mail to "freebsd-questions-unsubscribe at freebsd.org"
> 
> 
>