Re: Hardware related question: 3ware 9500S

Raid 5 on the 9550SX is supposed to be significantly better than the 9500
series.

I would be carefull of benchmarks listed out there. For instance, whilst
looking for supporting material, I came cross this gem:
http://www.gamepc.com/labs/print_content.asp?id=9550sx4lp&cookie%5Ftest=1

They claim the they used a Tyan Thunder K8WE motherboard, and installed the
RAID controllers in a 64-bit 133MHz PCI-X slot. This motherboard doesn't
have any 64-bit 133Mhz PCI-X slots! (
http://www.tyan.com/products/html/tigerk8we_spec.html)
It's no wonder that the other raid controllers showed significantly less
performance than the PCI-e card.

This review from tomshardware:
http://www.tomshardware.com/2005/10/31/sata_spells_trouble_for_scsi_raid/page13.html

Suggests that the 9550SX is at least competitive with the others.

I know I like the 3ware/AMCC cards because of their very good RAID 10
performance. I'm not a big RAID 5 fan. RAID 5 sufferes the read before
write penalty problem that make RAID 5 writes very slow, particularly
noticebale in OLTP applications. RAID 10 will almost always offer better
write perfomance.

I wish we could set up an organization to do benchmarks with pgbench on
various different RAID controllers/drives and publish the results. I know I
would pay money for that.

Alex

On 4/15/06, Francisco Reyes <lists(at)stringsutils(dot)com> wrote:
>
> Merlin Moncure writes:
>
> > escalade is a fairly full featured raid controller for the price.
> > consider it the ford taurus of raid controllers, it's functional and
> > practical but not sexy. Their S line is not native sata but operates
> > over a pata->sata bridge. Stay away from raid 5.
>
> Do you know if their raid 5 is better in the new 9550SX?
>
> Or is the "Stay away from raid 5" more of a general comment that this type
> of raid is not good for DBs?
>
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