imap checkpoint and slow access to mailboxes

[Marco]

Hello,

  I run  Cyrus IMAP v2.4.17-Invoca-RPM-2.4.17-6.el6 wit about 2500 
mailboxes (about 3 TB).

Days ago I had a disk problem (read only disk access) with some trouble 
on server.

Now I see a ton of these messages:

2016-10-07T02:38:16.596528+02:00 ucstore cyrus/imap[12693]: skiplist: 
checkpointed /var/lib/imap/domain/Q/domain.it/user/A/<xxxx>^<xxxx.seen 
(19 records, 1700 bytes) in 0 seconds

and access to mailboxes is slower than normal.

I though a sort of recovery started, but the problem on disk happens 
three days ago.

Also incremental squatter takes about 15 hours in place of 2 hours.

Do you have any hint how to solve this problem?


Thank you very much.
Best Regards
Marco