On 05/04/2011 09:44 AM, Srinivas Eeda wrote: > Yes, there is locking involved. Extending a file needs an exclusive > lock. Grepping a file needs read lock. If the same node(lets call it > writer node) does extending and grepping, then grep already has a > compatible lock and the data is also cached on this node. When another > node does the grep(lets call it reader node), then it needs to acquire > read lock. This requires the writer node to down grade the lock which > requires the node to flush data to the disk. Then the reader node has to > read the data to the cache. So when grep is done on the reader node, > there are additional messages and additional I/O's to the disk are done.
Any workarounds? Obviously doing read and append on the same node is one way. Could the logger extend the file in a different way? The software is homegrown, we could modify it to make it more OCFS2-friendly, if that's possible. OCFS2 settings to tinker with? > Just curious, do you have any numbers to show the time difference? Not as of now. I switched it back to "fast mode" (read and append on the same node) because it was pretty annoying. I'll see if I can run some tests one of these days. -- Florin Andrei http://florin.myip.org/ _______________________________________________ Ocfs2-users mailing list Ocfs2-users@oss.oracle.com http://oss.oracle.com/mailman/listinfo/ocfs2-users
