[HCoop-Discuss] Finalizing Hardware Upgrade

[Peter Gammie]

On 10/11/2009, at 11:49 AM, Clinton Ebadi wrote:

> 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.

This seems to be a non sequitur to me: I'm concerned about days of  
outage as the entire RAID gets rebuilt, if the controller carks it and  
no compatible card is available.

In utter ignorance, I wonder if the performance of software RAID is so  
much worse than hardware RAID. I grant that Linux has had some nasty  
interactions amongst the various parts of the filesystem in the past  
(e.g. NFS and ext3 IIRC) that might make hardware RAID more reliable  
anyway.

I know some people who do run large (multi-terabyte) RAID setups, I  
can enquire what they do if you like.

cheers
peter