performance issue (imap spool on san)

[Rudy Gevaert]

Hi,

I've installed the latest cyrus release and I'm having trouble with 
large mailboxes.

I was going to try if the 4Gig limit is gone and I'm filling up a 
mailbox with mails.

If I open the mailbox trough mutt it gets loaded at a acceptable 
(lighting fast) speed.  However when using thunderbird it gets very 
slow, I haven't been able to open the mailbox of 294M.

Attaching strace to the pid I see only the following messages:

open("/mail/mail2/imap/domain/m/mail.ugent.be/r/user/rudy^gevaert2/203750.", 
O_RDONLY) = 15
fstat64(15, {st_mode=S_IFREG|0600, st_size=23898, ...}) = 0
mmap2(NULL, 23898, PROT_READ, MAP_SHARED, 15, 0) = 0xb5749000
close(15)                               = 0
munmap(0xb5749000, 23898)               = 0
open("/mail/mail2/imap/domain/m/mail.ugent.be/r/user/rudy^gevaert2/203751.", 
O_RDONLY) = 15
fstat64(15, {st_mode=S_IFREG|0600, st_size=23898, ...}) = 0
mmap2(NULL, 23898, PROT_READ, MAP_SHARED, 15, 0) = 0xb5749000
close(15)                               = 0
munmap(0xb5749000, 23898)               = 0
open("/mail/mail2/imap/domain/m/mail.ugent.be/r/user/rudy^gevaert2/203752.", 
O_RDONLY) = 15
fstat64(15, {st_mode=S_IFREG|0600, st_size=23898, ...}) = 0
mmap2(NULL, 23898, PROT_READ, MAP_SHARED, 15, 0) = 0xb5749000

The above logs are only an extract of the output.  These messages are 
going in slow bursts.

The imap spool and configdirectory are on a SAN.  How can I further 
debug this?

Thanks in advance,

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Rudy Gevaert          Rudy.Gevaert at UGent.be          tel:+32 9 264 4734
Directie ICT, afd. Infrastructuur  Direction ICT, Infrastructure dept.
Groep Systemen                     Systems group
Universiteit Gent                  Ghent University
Krijgslaan 281, gebouw S9, 9000 Gent, Belgie               www.UGent.be
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