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From: Wojciech Puchar <wojtek@wojtek.tensor.gdynia.pl>
To: Maxim Khitrov <mkhitrov@gmail.com>
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Cc: Free BSD Questions list <freebsd-questions@freebsd.org>
Subject: Re: Software raid5 through a sata port multiplier
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> thinking that a software raid5 solution may not be such a bad idea.

software raid5 isn't any more bad than hardware raid5 most cases.

just raid5 is bad if you use it in ANY type of load except:

a) mostly reads - then set LARGE RAID stripe size
b) mostly huge files - then set small RAID stripe size to have highest 
single thread transfer, or large to have higher concurency.

EVERY OTHER case is bad case for RAID5 - just remember small write on 
RAID5=2 reads+2 writes on disks.


> The question is what port multiplier hardware does FreeBSD 7 support?

it unfortunately doesn't. but your hardware RAID controllers drive disks 
by itself and presents virtual drives to system, and system has nothing to 
do with it.
so ask manufacturer if it supports port multipliers.