huge increase in storage activity afther dovecot upgrade

Adrian Minta adrian.minta at
Thu Nov 15 22:24:19 EET 2018

Yes, multiple imap servers using one shared nfs storage. With the same 
config on 2.2.13 the public interface traffic was similar to the storage 
interface, around 100 mbps.

After we switch to 2.2.27 the storage interface traffic jumped 10 times 
while the public interface stayed the same. This make us thinking that 
something is wrong and each time a user logs in the whole Inbox content 
is read by dovecot.

What you are suggesting goes against the documentations and it may not 
be save, but I will give a  thought.

On 11/15/18 6:23 AM, Adi Pircalabu wrote:
> Are you connecting to the same mailbox over NFS from multiple IMAP 
> servers? If not and, at any given time, any mailbox will be accessed 
> from a single NFS client, try to "dupe" Dovecot into thinking it's not 
> using NFS. We're running quite successfully such setup with NFSv3 over 
> TCP, which turned out to be the fastest and most reliable throughout 
> the years. Here are the mount options:
> rw,noatime,nodiratime,vers=3,rsize=1048576,wsize=1048576,namlen=255,hard,nordirplus,proto=tcp,timeo=600,retrans=2,sec=sys,mountvers=3,mountport=1892,mountproto=tcp,local_lock=none 
> On the Dovecot side we're running with:
> lock_method = dotlock
> mail_fsync = never
> mail_nfs_index = no
> mail_nfs_storage = no
> maildir_very_dirty_syncs = yes
> mmap_disable = yes
> protocol lda {
>   mail_fsync = optimized
> }
> protocol lmtp {
>   mail_fsync = optimized
> }
> Note: we're using Maildir and the usual "works for me(c), may not work 
> for everyone" applies.
Best regards,
Adrian Minta

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