[Samba] CTDB / Samba / GFS2 - Performance - with Picture Link

Volker Lendecke Volker.Lendecke at SerNet.DE
Tue Nov 27 09:04:45 MST 2012

On Tue, Nov 27, 2012 at 03:50:40PM +0000, Vogel, Sven wrote:
> Hi Volker,
> thanks for the fast reply. So used the strace command. I am not so a strace specialist but is it possible that the problem are the many polls?`
> 12513 15:33:24.593065 poll([{fd=9, events=POLLIN|POLLHUP}, {fd=7, events=POLLIN|POLLHUP}, {fd=40, events=POLLIN|POLLHUP}, {fd=32, events=POLLIN|POLLHUP}, {fd=34, events=POLLIN|POLLHUP}], 5, 4436) = 1 ([{fd=32, revents=POLLIN}]) <0.002497>
> 12513 15:33:24.595615 read(32, "\0\0\0T", 4) = 4 <0.000017>
> i added a link to the strace. I dont see which syscalls take long. There are such many syscalls in any second so i dont know whats normal. :-|
> http://dev.kupper-computer.com/intern/smbd.txt
> Did you have any idea?

One question -- do you have your brlock.tdb on gfs? If so,
move them to a local file system, they will be taken care of
by ctdb. Your fcntl calls on that seem slow. Also, you might
want to try "posix locking = no". There is a call at
timestamp 15:32:47.383963, 1.9 seconds to find out whether a
range is locked. That shows that at this point in time GFS
was busy regarding fcntl locks. Also, your network or your
client seems to have a problem. For example at timestamp
15:32:51.837717 we are waiting 30 milliseconds for a new
request from the client. This is very long for a client
continuously trying to write.


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