Tomorrow we migrate to new Zimbra server (net hardware, new OS, new Zimbra version).
was: Release 7.1.3_GA_3346.DEBIAN5_64 DEBIAN5_64 FOSS edition.
now:Release 8.0.4.GA.5737.UBUNTU12.64 UBUNTU12_64 FOSS edition.
for migration we use Zextras backup/restore
Migration was completed successfully, but now we have big troubles with IMAP mail clients.
I have over 150 Thunderbird email clients, which use IMAP with SSL. and all clients have a big troubles - IMAP work very slow.
I don't have any troubles with Zimbra mailbox WEB-interface, but access to Admin panel also work extremely slow.
at top I can see that server not overloaded (new hardware has more performance at old server we don't have such problems).
at trafshow I saw what only couple clients generates traffic (I thins it's IMAP sync).
I have no idea, where I should look for problem. Any help will be appreciated!