On Fri, 16 Oct 2009, Holger Kiehl wrote:
On Fri, 16 Oct 2009, Justin Piszcz wrote:
Hi,
I have the same problem with mdadm/raid-1, if you do not limit the speed in
the speed_limit_min paramter, it will starve the I/O from all other
processes and result in the same problem you are having.
But in my case speed_limit_min was set to 1000 and speed_limit_max was 200000
(ie. the default) and this still caused all process to hang in D-state. Only
lowering speed_limit_max helped to make the system responsive again.
yep, MD raid will use every bit of disk bandwidth there is.
even worse, the speed_limit_* appears to be per-drive, not per array
(although the /proc/mdstat info is per array), so if you have lots of
drives on one controller card it will kill the system and still think that
it's not maxed out.
I did a 45 disk array hooked into two PCI slots and found that I needed to
set speed_limit_max _very_ low to avoid this sort of problem.
David Lang
But for me I'm not sure about the reconstruction-- this happens for me
during a raid verify/check.
This was also the case for me, during a raid verify/check.
Holger
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