configuration choices with Dell CERC (adaptec 2610SA)

[Herve Boulouis]

Le 26/11/2005  15:07, user a écrit:
> 
> Ok.  It is.  However, my experience has been that no matter how rock solid
> the datacenter provided, UPS backed power is, there is a power
> interruption about every 1-2 years (and this experience comes from very
> very good datacenters - from Level3 to UUnet, etc.) ... so ... let's say I

<troll>
American datacenters do not seem to be as reliable as (some) french ones :)
</troll>

> Assuming freebsd 6.0 and UFS2 ... is it just an fsck, or is there a
> potential for some real problems if the kernel thinks something is totally
> committed, but it never makes it to the drive ?

That is impossible to predict. My personal point of view is that the performance
gain is worth the risk. YMMV.

> I am going to set it to "low" then ... my experience is that a failed disk
> often rebuilds itself only to re-fail shortly thereafter, thus making
> possible a continuous loop of rebuilding over and over ... which would
> essentially take the system offline if all resources were dedicated to the
> rebuild.  Comments ?

The controller never tries to rebuild on a failed disk. If you have dedicated
spare disks it will try to rebuild the data on the spares. If you have no spare,
you have to either change the failed disk or unplug and replug it if you think
the failure is transient. So there is no possible loop here.

-- 
Herve Boulouis