Re: RAID controllers for Postgresql on large setups

On May 12, 2008, at 10:04 PM, Francisco Reyes wrote:

> Adaptec 2120 SCSI controller (64MB of cache).
>
> The servers have mostly have 12 drives in RAID 10.
> We are going to redo one machine to compare RAID 10 vs RAID 50.
> Mostly to see if the perfomance is close, the space gain may be
> usefull.

with only 64Mb of cache, you will see degradation of performance.
from my experience, the adaptec controllers are not the best choice,
but that's mostly FreeBSD experience. And if you don't have a BBU,
you're not benefitting from the write-back cache at all so it is kind
of moot.

If you want to buy a couple of 2230SLP cards with 256Mb of RAM, I have
them for sale. They're identical to the 2130SLP but have two SCSI
channels per card instead of one. they both have BBUs, and are in
working condition. I retired them in favor of an external RAID
attached via Fibre Channel.