1 processor vs. 2
cswiger at mac.com
Wed Mar 3 13:57:31 PST 2004
On Mar 3, 2004, at 4:26 PM, Stefan Cars wrote:
> Okey, but if you would compare RAID-1 on two disks compared to RAID-5
> three disks then ? What would be the faster ?
RAID-1 will be about 50% faster than RAID-5 doing reads regardless of
size, and will also be *much* faster doing small writes-- by a factor
of 4, perhaps.
[ There is a potential optimization for RAID-5 using very large
writes-- ie, bigger than the RAID interleave size * (# of disks - 1)--
that might make it more comparable with RAID-1's performance, only I
believe FreeBSD breaks up large I/O requests into 32K or so, thus there
generally never is the potential to not read the data before writing. ]
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