Yet another RAID Question (YARQ)

[Alex Zbyslaw]

P.U.Kruppa wrote:

> our school has just received a new HP ProLiant and I set up FreeBSD 
> 5.4 -RELEASE with a RAID 1 system on it (using ciss driver).
> Is there any software tool which can show me the state of the two SCSI 
> discs (if one is failing or if they are mirrored sorrectly) or is it 
> sufficient to watch the little LEDs on the box?

That's a good question, and I only have a partial answer for you.  You 
can look at sysutils/smartmontools port which will show you the SMART 
status for the disks that it can see.  If you can see both disks (which 
I *think* would have devices like /dev/sd0, /dev/sd1) then you ought to 
know if the disks are failing.  SCSI disks, from my limited experience, 
don't show as much info as ATA disks, but so far both Quantum and 
Fujitsu do seem to have supported SMART at a basic level.  You should be 
able to tell what FreeBSD can see in the way of disks by examining 
/var/run/dmesg.boot.

A word of caution, though.  A Linux system (which I help administer) had 
two SCSI disks mounted as RAID-1 through some kind of Adaptec 
controller.  Recently the machine crashed and it transpires that one of 
the disks hadn't been written to since 2002!  I am told that the bootup 
screen showed the RAID-1 as working, and Linux could *only* see one 
virtual disk -- the supposed RAID mirror.  So, I think your question is 
a very good one!  We had (apparently) no way of knowing what was going 
on. The machine crashed with no messages whatsoever, after losing all 
access to its disks, and there was no indication that RAID-1 was not 
functioning.

I *think* that the RAID controller should spot when a disk is failing 
and notify you (through its driver) through console messages and 
/var/log/messages.  I too would love an answer to this question for any 
decent SCSI controller under FreeBSD (e.g. Dell PowerEdge 2850 with PERC 
4e/Di RAID controller).  Can you, in general, see through the RAID 
controller to monitor individual disks?

--Alex