[CentOS] Re: question about software Raid 1
John R Pierce
pierce at hogranch.com
Sun Sep 21 23:59:50 UTC 2008
> This makes sense. I'm pretty sure that tests that I've run in the past
> using bonnie++ or iozone showed faster reads with raid1 than with a
> single drive. I would think that if the drives are on seperate
> controllers (and depending upon the performance/capacity of the drives
> and controllers), there could be notable improvements.
with SATA or SAS, of course, every drive is on its own channel. even
with PATA, at 100 or 133Mbyte/sec, only the fastest newer drives would
saturate the bus doing two transfers concurrently.
now, after i wrote what I did above, I dug up the kernel.org 2.6.18
kernel that RHEL/CentOS 5 is based on, and it still had the older code
sequence as shown in that 'to do' list entry... but I didn't run the
RHEL patch sequences against it, its quite possible RHEL retrofitted
this patch to it.
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