From: Craig A. James <cjames@modgraph-usa.com>
To: Alan Hodgson <ahodgson@simkin.ca>
Cc: pgsql-performance@postgresql.org
Subject: Re: RAID 0 not as fast as expected
Date: Thu, 14 Sep 2006 14:35:00 -0700
Message-ID: <4509CB04.4020605@modgraph-usa.com> (raw)
In-Reply-To: <200609141136.03345@hal.medialogik.com>
References: <450999EC.8070601@modgraph-usa.com>
<200609141136.03345@hal.medialogik.com>
Alan Hodgson wrote:
> On Thursday 14 September 2006 11:05, "Craig A. James"
> <cjames@modgraph-usa.com> wrote:
>> I'm experiment with RAID, looking for an inexpensive way to boost
>> performance. I bought 4 Seagate 7200.9 120 GB SATA drives and two SIIG
>> dual-port SATA cards. (NB: I don't plan to run RAID 0 in production,
>> probably RAID 10, so no need to comment on the failure rate of RAID 0.)
>>
>
> Are those PCI cards? If yes, it's just a bus bandwidth limit.
Ok, that makes sense.
One SATA disk = 52 MB/sec
4-disk RAID0 = 106 MB/sec
PCI at 33 MHz x 32 bits (4 bytes) = 132 MB/sec.
I guess getting to 80% of the theoretical speed is as much as I should expect.
Thanks,
Craig
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To: pgsql-performance@postgresql.org
Cc: cjames@modgraph-usa.com, ahodgson@simkin.ca
Subject: Re: RAID 0 not as fast as expected
In-Reply-To: <4509CB04.4020605@modgraph-usa.com>
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