[Dovecot] nfs error fcntl(read-lock) locking failed for file

[Rajesh M]

hi

i am using qmailtoaster with dovecot version 2

mailbox format is maildir

i have a domain with around 5000 users which are distributed over 2 servers

webmail (squirrelmail) runs using dovecot v2 is being used from server
number one

server number 2 had all the data stored in it and also has pop and smtp
running from it. i am not using dovecot for pop as yet

on the server with dovecot i get such errors in the log file

access to data on server number 2 is via nfs

on server number 1 i get errors as such
Error: fcntl(read-lock) locking failed for file Input/output error
squirrelmail gives error imap connection closed and i am not able to login


so i set the parameters as such in the dovecot conf file and the error
stopped

mmap_disable=yes
dotlock_use_excl = yes
lock_method = dotlock

can somebody please advise me if the above is correct ?

or is it preferred to use fcntl with lockd (note that my mailbox is
maildir format)

thanks very much for your help

rajesh