Re: which dual-CPU hardware/OS is fastest for PostgreSQL?

Hi,

From what I've been reading on the list for the last few months, adaptec
isn't that good when it comes to RAID controllers, but LSI keeps popping up.
Is there any particual models that are recommended as I'm in the market for
two new servers both with RAID controllers. The server specs I'm thinking
are as follows:

Box 1
Fedora 64bit core 3
4 GB RAM (2GB per CPU)
2 x Opteron CPU ???
Tyan K8S
LSI® 53C1030 U320 SCSI controller Dual-channel

Box 2
Fedora 64bit core 3
2 GB RAM (1GB per CPU)
2 x Opteron CPU ???
Tyan K8S
LSI® 53C1030 U320 SCSI controller Dual-channel

This motherboard has can "Connects to PCI-X Bridge A, LSI® ZCR (Zero Channel
RAID) support (SCSI Interface Steering Logic)". I believe this means I can
get a LSI MegaRAID 320-0 which a few have mentioned on the list
(http://www.lsilogic.com/products/megaraid/scsi_320_0.html). It supports
RAID 10 and supports battery backed cache. Anyone had any experience with
this?

Any other particular controller that people recommend? From what I've been
reading RAID 10 and battery backed cache sound like things I need. :)

Thanks,

Benjamin Wragg

-----Original Message-----
From: pgsql-performance-owner(at)postgresql(dot)org
[mailto:pgsql-performance-owner(at)postgresql(dot)org] On Behalf Of Josh Berkus
Sent: Tuesday, 11 January 2005 5:35 PM
To: pgsql-performance(at)postgresql(dot)org
Cc: Christopher Browne
Subject: Re: [PERFORM] which dual-CPU hardware/OS is fastest for PostgreSQL?

Chris,

> I don't know so much about FreeBSD's handling of this, but on Linux,
> there's pretty strong indication that _SOFTWARE_ RAID is faster than
> hardware RAID.

Certainly better than an Adaptec. But not necessarily better than a
medium-end RAID card, like an LSI. It really depends on the quality of the
controller.

Also, expected concurrent activity should influence you. On a dedicated
database server, you'll seldom max out the CPU but will often max of the
disk, so the CPU required by software RAID is "free". However, if you have

a Web/PG/E-mail box which frequently hits 100% CPU, then even a lower-end
RAID card can be beneficial simply by taking load off the CPU.

--
Josh Berkus
Aglio Database Solutions
San Francisco

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