>>>>> "christoph" == christoph pirchl <[EMAIL PROTECTED]> writes:
...
christoph> You forgot RAID 4 it is stripping with parity on one Disc ! It s
christoph> normally not used any longer as i know !
Actually, a few years back I sat in on a presentation put on by Network
Appliance. It seems that they (at least at that time) used RAID 4. The
downside to RAID 4 is that the parity drive is normally the bottleneck
(since the parity must be written to with every write I/O -- no matter
which of the other drives are written to, the parity drive gets hit as
well)
It seems that Network Appliance's log-structured filesystem got around the
problem by somehow reducing the parity drive's I/O load. Then, because the
rest of the drives in a RAID 4 array follow a set pattern of sector
interleaving, it was possible to allow additional drives to be added into
the array dynamically -- it was a pretty cool solution to a tough
problem...
Ed
--
Ed Bailey Red Hat, Inc. http://www.redhat.com/
_______________________________________________
Redhat-list mailing list
[EMAIL PROTECTED]
https://listman.redhat.com/mailman/listinfo/redhat-list
