Rustedt, Florian wrote:
Hello List,
If the speed on RAID 0 is based on reading out in parallel, then it must be
the same on RAID 1, mustn't it?
On RAID 1, it is possible, to read two blocks in parallel to speed up, too.
I tried to measure this some weeks ago, but i couldn't get over the
read-performance of a single disk on my raid 1, so that means, that the
software-raid does not use this easy possibility to speed up?
We've had this discussion before, and the RAID code does not take
advantage of running reads in parallel to satisfy readahead or anything
else. I seen it said that this is on a per-thread basis, but a simple
test suggests that it's on a process basis, setting two threads to read
alternating 10k blocks as fast as possible ran no faster than a single
thread. However, running against RAID-10, even a single thread seemed to
run far faster than the speed of a single drive.
Lightly tested, don't take this as the last word.
--
bill davidsen <[EMAIL PROTECTED]>
CTO TMR Associates, Inc
Doing interesting things with small computers since 1979
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