[Dovecot] performance of maildir on ocfs2

[luben karavelov]

On  1.05.2010 00:32, Timo Sirainen wrote:
>
> v1.2 dbox is similar to v2.0's dbox, but not identical. v2.0 dbox is simpler and faster. Also dbox and mdbox are different, although they share some code. http://wiki.dovecot.org/MailboxFormat/dbox
>
> Anyway, v2.0 is supposed to be able to read v1.2's dbox, but 1) I haven't tested it recently and 2) that's only if the dbox doesn't contain any maildir-migration files (so all mail files are u.* files, no maildir files). I'm kind of hoping the dbox/maildir hybrids aren't all that popular and maybe I don't need to worry about them.. :)
>
I have done some test here.

1st. There is some problem with imap + quota plugin. the corresponding logs:

May  1 03:46:33 rho2 dovecot: imap(luben at test.dpv.bg): Panic: file 
index-transaction.c: line 145 (index_transaction_rollback): assertion 
failed: (box->transaction_count > 0 || box->view->transactions == 0)
May  1 03:46:33 rho2 dovecot: imap(luben at test.dpv.bg): Raw backtrace: 
/usr/lib/dovecot/libdovecot.so.0 [0x7f6e230114c2] -> 
/usr/lib/dovecot/libdovecot.so.0 [0x7f6e2301152a] -> 
/usr/lib/dovecot/libdovecot.so.0(i_error+0) [0x7f6e230118d3] -> 
/usr/lib/dovecot/libdovecot-storage.so.0 [0x7f6e232c0d24] -> 
/usr/lib/dovecot/modules/lib10_quota_plugin.so [0x7f6e21294021] -> 
/usr/lib/dovecot/modules/lib10_quota_plugin.so [0x7f6e21293a90] -> 
/usr/lib/dovecot/libdovecot-storage.so.0(sdbox_sync_begin+0x45e) 
[0x7f6e232c2bee] -> 
/usr/lib/dovecot/libdovecot-storage.so.0(sdbox_transaction_save_commit_pre+0x70) 
[0x7f6e232c33f0] -> /usr/lib/dovecot/libdovecot-storage.so.0 
[0x7f6e232c1138] -> 
/usr/lib/dovecot/libdovecot-storage.so.0(mail_index_transaction_commit_full+0x97) 
[0x7f6e23290957] -> 
/usr/lib/dovecot/libdovecot-storage.so.0(index_transaction_commit+0x8b) 
[0x7f6e232c0dbb] -> /usr/lib/dovecot/modules/lib10_quota_plugin.so 
[0x7f6e212940a4] -> 
/usr/lib/dovecot/libdovecot-storage.so.0(mailbox_transaction_commit_get_changes+
May  1 03:46:33 rho2 dovecot: master: service(imap): child 5621 killed 
with signal 6 (core dumps disabled)
May  1 03:46:33 rho2 dovecot: imap(luben at test.dpv.bg): dbox: File 
unexpectedly lost: 
/var/www/149444/mail/122-dbox/mailboxes/INBOX/dbox-Mails/u.3226
...

So I have disabled all imap plugins except autocreate and have run the 
dbox/mdbox
test with dovecot v2.0b4 and with v1.2.11. Here are the results:

nologout  10 1111 1036   10 2111 3071  755 1680 2111 2111       1.2.11  dbox
logout   544  272  263  542  538  753  191  426  538  540 1088  1.2.11  dbox
nologout  10 1182 1182   10 2367 3389  808 1919 2367 2367       2.0b4   dbox
logout   531  266  265  529  517  720   76  414  517  526 1072  2.0b4   dbox
nologout  10 1074 1012   10 2087 3045  725 1622 2087 2087       2.0b4   
mdbox
logout   504  265  242  503  491  660  135  397  491  502 1012  2.0b4   
mdbox


So, on this test setup, there is no much difference between dbox/mdbox. 
May be in other
setups it will show differend results. I have seen differend  comparison 
proportions
using diffened servers (pre-core 64bit xeons vs core2-quad) even when 
using the same
storage and filesystem.

When v2 stabilizes, I will consider migrating for the greater 
flexibility (altstorage,
LMTP etc.)

Best regards and thanks for the great work
luben