[HCoop-Discuss] Finalizing Hardware Upgrade

[Clinton Ebadi]

Peter Gammie <peteg42 at gmail.com> writes:

>> We are looking now to nail down the final specs of the machines and
>> purchase it within the next few weeks. I am leaning toward getting a
>> hardware RAID5 and using either three 1TB or 500G drives for AFS and a
>> smaller (lowest sized drives before the cost/G starts increasing)  
>> RAID1
>> for the local file system on the machines. Suggestions are welcome.
>
> I am not a sysadmin of any stripe, but I get the impression that  
> hardware RAID is asking for trouble.
>
> Specifically, if the controller fails, then you may have to replace it  
> with exactly the same controller if you want to avoid restoring from  
> backups. This may prove difficult in a few years' time.
>
> I'd expect software RAID to be immune to this issue.

The chances of the hardware RAID card dying is fairly low; if it does
then it is a standard Dell part and IIRC they provide compatible
controllers for a good number of years.

The Hardware RAID in the PowerEdge series has a 256M battery backed
cache making it pretty fast and resilient against power failure
(according to the docs it can lose power for several *days* before
losing the write cache; since we'd be using it for our most heavily used
file system its performance is pretty essential.

-- 
Danielle: well road signs were pissing me off
Danielle: I took one of them out, but the other haven't followed as
          planned