Quentin Hartman wrote:
On Nov 15, 2007 9:29 AM, Ben Barrett <[EMAIL PROTECTED]
<mailto:[EMAIL PROTECTED]>> wrote:
https://help.ubuntu.com/community/FakeRaidHowto ("Fake" raid is
soft raid, nothing really fake about it)
I don't know why software RAID does not get more respect these
days. When processors were just babies,
hardware raid was needed for reasonable performance, but now soft
raid is really fast, unless you're comparing
it with enterprise-grade NAS setups. IMO soft raid is fine for
non-SCSI RAIDs :)
Just a clarification on this point. Fakeraid is (every time I've seen
it, anyway..) used to refer to raid cards that claim to have RAID, but
actually offload all the raid functionality to the host machine via a
driver. Most of these cards only have a firmware program to manage the
drives, nothing else is done in hardware. Hence the name Fakeraid, it
looks like hardware raid, but it's not, it's fake. This is also
sometimes called firmware raid. A very small percentage (I only know
of one) of these cards also have a hardware XOR engine for offloading
the work required for Raid 5. Ooohhh... Fakeraid+ :)
My rule of thumb is to use true hardware when it's available, and to
require it in "important" servers. Failing that, I use software raid.
You get 80-90% of the performance of hardware raid in most use cases,
and management is consistent from machine to machine. The
"middleground" Fakeraid gets you none of the performance advantages of
true hardware raid since everything is offloaded to the host anyway,
and introduces a whole bunch of vendor-specific complications, so I
avoid it entirely.
I'll throw in a 'yup, me too'. Fakeraid is a tremendous headache waiting
to happen. Either go true hardware raid (if you've got the budget AND
you can afford to have a spare card on hand) or go software raid.
garl
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