>For most SAS operations I/O is the bottleneck. I would put as much
>money into the drives as possible. I've had good experiences with IDE
>RAID 0 (eg a two-disk RAID 0 system almost doubled the throughput
>speed). I would guess that RAID 5 would be just as fast reading.
>Sustained transfer speed is the key (rather than seek times). You might
>get more back for the buck using SATA than SCSI (particularly if the
>machine won't be in continuous use).
>When using RAID, I found best performance when I set bufsize and
>ubufsize at twice the RAID stripe size (see Davis and Ralston
Bruce makes a very good point here. (As usual!) I/O is usually the killer
in data manipulations like you want. But there is an additional
SAS has a SASFILE statement which allows you to load a data set into RAM,
for much faster access and data mangling. So make sure to cram enough
RAM into your machine to handle any size of data set you're likely to use,
and then you can use SASFILE to speed up intermediate processing.
You still have to read the darn thing once (at a minimum) off your hard
drives, though. :-)
David L. Cassell
3115 NW Norwood Pl.
Corvallis OR 97330
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