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1. Re: Queue cache or persistance I/O slowdown
alwyn Oct 29, 2002 11:54 PM (in response to jaywright00)Look in db/jbossmq/file. Do a lot of fast subsequent ls -la's and you'll see a bunch of small files being created and destroyed.
I solved it with a ramdisk. Alternative is rollinglogged PersistenceManager, but it kills performance by about 300 messages/second.
Strange things also happen when you actually want persistence... -
2. Re: Queue cache or persistance I/O slowdown
jaywright00 Oct 30, 2002 11:54 AM (in response to jaywright00)
Actually i don't see that, not in db/jbossmq/file or db/jbossmq/file/QUEUE.myQueue. Do you know what is being written and by which class?
Most importantly, can it be turned off? Either through configs or extending a class (or editting a class) and rebuilding jboss?
Why would this disk io be necessary? -
3. Re: Queue cache or persistance I/O slowdown
kelbahi Oct 31, 2002 2:44 AM (in response to jaywright00)you may want to check if the in memory queue is being written to disk. This is governed by
org.jboss.mq.server.MessageCache
and
org.jboss.mq.pm.file.CacheStore
looks like 1 message per file once the vm is the size specifiec by messageCache.
/Kel -
4. Re: Queue cache or persistance I/O slowdown
alwyn Nov 4, 2002 2:30 AM (in response to jaywright00)The message cache writes to tmp/jbossmq I think...
In my tests the Cache values were set in the region of 1.5Gb
and I never came close to reach that so I suspect it is the Persistence Manager.
I'm toying with the idea of writing my own PM that does nothing, but that is a bit of a low priority idea at the moment.