Hi David,
We're running Solr 1.1 and we're seeing intermittent cases where
Solr stops responding to HTTP requests. It seems like the listener
on port 8983 just doesn't respond.
When we started using solr we encountered the same problem. We are
currently running solr 1.0 (!) with tomcat 5.5 on two servers. Our index
has 16 million documents and is updated about 10 times per day
(depending on the incoming data).
We found out three factors which may be responsible for the problems:
1) Memory. Our two servers running solr have 8 GB each and we have set
the option -Xmx2560M for tomcat. We got rid of the most problems by
increasing the memory. We had no success trying to get solr running with
just 4GB in the machine.
2) Disk activity. This is strange. We found out that using rsync on the
machine sometimes makes solr stop responding. We cound avoid this by
setting an upper limit on the bandwidth rsync uses. Just recently we
found out that even copying big files on the machine stops solr. So It
seems that high disk activity might cause problems for solr.
(We have a MySQL database running on the same servers. Normal operation
seems to be no problem, even if the servers have high load.)
3) Reading and writing at the same time. We had no chance updating an
index while querying it at the same time. So when the index on our
master server is updated all queries will go to the second server.
I think that some of the problems are solved in newer versions of solr.
We are going to test that in the near future.
Marcus
