On Tue, 28 Jun 2005 16:10:32 -0400 Jason Crawford <[EMAIL PROTECTED]> wrote:

> If you want the closest you can get to SCSI without actually going
> SCSI, try the LSI Logic MegaRAID SATA 300-8X controller. It uses the
> SATA-II spec, so you get 3.0gbps throughput, plus you have NCQ, which
> can queue up to 32 commands (IIRC). It's still no U320 SCSI setup, but
> it's much much much better than PATA or even SATA-I, which is half the
> speed, and normally doesn't support NCQ at all.

recent discussion on one of the PostgreSQL lists suggests that at the
current state of the art, SATA and SCSI are about comparable for
read intensive ("SELECT") operations, but SCSI still outperforms
SATA for write intensive ("INSERT" and "UPDATE") operations.

additionally, i saw someone mention RAID 5 in there somewhere. RAID
5 is fine for read operations, but RAID 10 will outperform it in write
intensive operations.

so if i were managing a lot of disk i/o (say, a really really huge,busy
mail server), i'd probably look at RAID 10 with a good SCSI array.

richard
-- 
Richard Welty                                         [EMAIL PROTECTED]
Averill Park Networking
    Java, PHP, PostgreSQL, Unix, Linux, IP Network Engineering, Security
      "Well, if you're not going to expect unexpected flames,
         what's the point of going anywhere?" -- Truckle the Uncivil

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