We're having a lot of trouble currently with tomcat crashing with a "Too
many open files" error. This is happening roughly twice a day -- I am
restarting tomcat every morning, and usually get a call around lunch time
that it has crashed and need to restart again.
Restart is quick and fixes the problem, temporarily, but naturally I wish it
didn't happen at all.
I did some digging and found a thread from this list from last year, which
petered out without apparent resolution, but where Mark Diggory suggested
tinkering with the fd.files-max value in sysctl.conf.
[
http://sourceforge.net/mailarchive/message.php?msg_id=E1Grhzs-0000Nj-JN%40ma
il.sourceforge.net ]
Well, I tried that, but it made no difference. So, back to Google, where I
found (searching for "files-nr") that you can list all the open file handles
used by a process, using
# ls -l /proc/PID/fd/
where PID is the process id.
So using this with the pid for the DSpace tomcat, I found lots of items like
this:
lr-x------ 1 uals uals 64 Dec 20 16:30 237 -> /data/dspace/search/_vzb.cfs
(deleted)
This is a symlink to one of the lucene index "overflow" files, which [in my
limited understanding] are dynamically created and deleted as the index
grows. These "deleted" items increase in number over time, and I imagine
DSpace eventually hits the ulimit for open files (1024) and dies.
So I think the problem may be due to the lucene indexing not releasing file
descriptors when they are deleted. Certainly, watching the list over an hour
I've seen the number of "deleted" lines rise steadily. I guess we're
noticing this as a problem here because of the very large amount of editing
work we're engaged in currently. Other sites with a more "sedate" use of
DSpace might never run into it.
Well, that's how it looks to me right now. Nothing I can do about it, but
maybe someone expert in the lucene side of DSpace could look into it?
Cheers. :D
Stephen Thomas,
Senior Systems Analyst,
University of Adelaide Library
UNIVERSITY OF ADELAIDE SA 5005 AUSTRALIA
Phone: +61 8 830 35190
Fax: +61 8 830 34369
Email: [EMAIL PROTECTED]
URL: http://www.adelaide.edu.au/directory/stephen.thomas
CRICOS Provider Number 00123M
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