On Thu, 18 Sep 2008 21:28:27 -0500, "Peter Olcott"
wrote:


"kony" wrote in message
.. .
On Thu, 18 Sep 2008 05:47:43 -0500, "Peter Olcott"
wrote:

I want to build a software based RAID system, and need to
have simultaneous access to 24 drives. I will probably go
with SAS controllers and SATA drives. From what I recall
most drive controllers can only handle 4 drives, and most
motherboards only have four fast PCI express slots. I need
a
way to hook up 24 drives to no more than 4 slots. One easy
way would be to get a SAS controller card that can handle
24
drives without specifying a RAID level. Can this be done?


Yes, if the card supports single drive spans. That's a
very
common feature on lower end raid cards but for one that
can
handle 24 drives I don't know.

I could not find anything about this on google [single drive
spans]
[single drive span] [drive span]


Look at the instruction manual for the card you're
considering.

A multi-drive span just creates a single logical volume that
is the sum of the individual drive members. For example two
250GB drives in a multi-drive span would create a 500GB
logical volume. Unlike RAID0 it doesn't stripe data across
both drives, it starts at the begining of one and starts on
the second after the end of the first.

A single-drive span is one that only has one member in it,
is typically how a drive is used on any non-raid controller.