Running 1.0.rc22
We have a single file server, running NFS (Single large sas disk) with about 80Gb of mail. mount -o remount,rsize=2048,wsize=2044,actimeo=0,soft,rw xx.xx.xx.xx:/mailboxes /nfs1
There are 3 front end pop/imap servers using an LVS director. Indexes are stored on each front end server.
-rw------- 1 admin 500 144 Mar 12 17:47 dovecot.index -rw------- 1 admin 500 10272 Mar 12 17:47 dovecot.index.cache -rw------- 1 admin 500 120 Mar 12 17:47 dovecot.index.log
Normally everything runs fine, there are about 1500 active pop accounts and 100 Imap. Typically, 10 to 20 pop accounts are downloading at anyone time, and there may be 10 or 20 active Imap sessions.
If we find that the index partition has got to 100% full and corrupted the indexes then we'll delete the entire index dir and let dovecot rebuild all the indexes however, we end up with 100mbit / 10Mb/sec of network traffic between the NFS server and the pop/imap servers. The nfs server load climbs to 20+ as does the load on the front end mail servers.
It can take 4 or 5 hours for the indexes to rebuild during which time imap is slow but works and pop downloads all end up with dead processes that need clearing every few minutes.
admin 5869 0.0 0.1 4384 1060 ? D 17:56 0:00 \_ pop3 [info@.co.uk 180.98] admin 5877 0.0 0.1 4392 1112 ? D 17:57 0:00 \_ pop3 [bro94 62.182] admin 5879 0.0 0.1 4396 1052 ? D 17:57 0:00 \_ pop3 [spamcatch@.com 81.163] admin 5884 0.0 0.1 4392 1056 ? D 17:57 0:00 \_ pop3 [ctaylor@.com 81.175]
Normally the nfs server delivers possibly 200Kbytes of traffic average spiking to 400Kbytes but the 900+Kbytes per second sustained rate for 5 or 6 hours is killing the service.
Is there something we've got wrong here?
(I know a Scsi raid NFS would help as would Gbit networking but I can't see the setup we've got as needing that sort of hardware spec?)
Thanks
John