On Mon, 22 May 2000, Dr J.C.W. Brooks wrote:
> I assumed that RAID just gave you disk redundancy, rather
> than performance increases, but could be wrong - wouldn't
> be the first time :)
What RAID gives you depends upon the configuration (level). The simplest
levels are level 0, which implements striping, i.e. your data is divided
between two or more disks. If any of the disks die your data is lost.
Data throughput is theoretically proportional to the number of disks
(other performance factors being unlimited). Level 1 simply mirrors the
data on multiple disks. This brings about no speed increase, but
increases data security. If any disk goes down you have an exact mirror
copy of it. The other raid levels implement variations and combinations
on these schemes, including error checking etc.
> As far as Linux and RAID arrays goes - I noticed in that
> SuSE are selling their own RAID array systems:
> http://www.suse.de/de/hardware
A number of hardware controllers are supported. As an aside, these should
not be confused with the software RAID emulation available under
Linux, which is apparently not as robust as the real thing.
Keith.
--
Keith Goatman
Medical Physics, Southampton General Hospital, UK.
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