Messages in this thread | | | Date | Fri, 5 Aug 2011 16:23:38 +0100 | From | Al Viro <> | Subject | Re: Q: cat /proc/mdstat blocking? |
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On Fri, Aug 05, 2011 at 02:02:49PM +0200, Ulrich Windl wrote: > Hi, > > I thought that /proc/mdstat just displays the current state of the MD RAIDs, not querying them, thus never blocking. Unfortunately I could observer a "cat /proc/mdstat" hanging for several seconds when one of the RAID1 legs was unavailable and multipathd was queueing requests to the leg. > > Practically this makes monitoring of the other RAIDs difficult when one bad device is enough to block /proc/mdstat. > > Now my question: Does it work as designed (i.e. as intended), or is this not as intended?
I suspect that something is holding all_mddevs_lock too long; that, or one of the subdrivers' spinlocks. Try to find out what it blocks on and what holds the lock in question...
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