El 04/07/12 23:55, Timo Sirainen escribió:
On 4.7.2012, at 21.49, Angel L. Mateo wrote:
Although nfs configuration is the same, there are a lot of differences
on readdir vs readdirplus nfs operations. In fact, in the old one we have 12%
readdir operations and 3% of readdirplus. And in the new one we have 46% of
readdirplus and no readdir operations.
I'm not entirely sure, but I think it's the kernel that decides if readdir or
readdirplus is used and Dovecot can't affect that decision. (Unless maybe
kernel does some heuristics.)
I think you are right. I guess that the differnce between my old system
(who uses readdir and readdirplus) and the new one (which just uses
readdirplus) is because of changes on the kernel. For some threads I
have read (for example,
http://www.spinics.net/lists/linux-nfs/msg19957.html) it seems that from
some version in kernel source (2.6.36 if I remmeber well) some nfs
improvements related with readdir and readdirplus (that makes nfs client
only uses readdirplus when it was better) and recents kernels always use
readdirplus.
Concluding... in my systems, with users with hugh mail folders
(thousands of mails) in maildir format, disabling rdirplus with mount
options (mount option nordirplus) increases performance (maybe we could
do more precise test and this could be documented in dovecot's nfs
documentation)
--
Angel L. Mateo Martínez
Sección de Telemática
Área de Tecnologías de la Información
y las Comunicaciones Aplicadas (ATICA)
http://www.um.es/atica
Tfo: 868887590
Fax: 868888337
