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Re: [Linux-cluster] GFS load average and locking



Stanley, Jon wrote:

2)  The locking statistics seems to be a huge mystery.  The lock total
doesn't seem to correspond to the number of open files that I have (I
hope!).  Here's the output of a 'cat /proc/gulm/lockspace - I can't
imagine that I have 300,000+ files open on this system at this point -
when are the locks released, or is this even an indication of how many
locks that are active at the current time?  What does the 'pending'
number mean?

GFS caches locks and normally won't release them (for performance reason). However, we do find this could cause latency issue, particularly after back up and/or tar command where lots of locks are accumulated into one single node that previously issued the backup command. Judging by your description of read latency and number of "shared" locks in your lockspace output, we do have a new tunable in to-be-released-soon RHEL3 Update 7 that allows admin to purge the locks. This seems to help several of (beta) customers to resolve their latency issues.

Other than this, do you find any error messages in your /var/log/messages file ?

-- Wendy


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