we need some information about cyrus-imap server

Simon Matter simon.matter at ch.sauter-bc.com
Tue Mar 14 14:55:08 EST 2006

> Jure Pečar wrote:
>> This sounds interesting. With two levels deep hash one would easily get
>> around 32k subdirs per dir limit most file systems have, which
>> basically leaves you without much choice but reiserfs.
> IBM jfs limit is 4G. That might be another option other than ReiserFS.

Another good option is XFS, especially now that delayed expunge can be
used. At least XFS handles millions of subdirs per dir without any
problems. I guess the whole directory hashing of programs like cyrus-imapd
or squid is in vain for those filesystems.
Are there other reasons to use dirhashing? Maybe internal limitations in
the applications itself?


>> I'm getting dangerously close to 32k users per letter and I don't feel
>> comfortable with fulldirhash. Even with fulldirhash one can have at
>> most 26*32k (~850k) users per instance, assuming nice even
>> distribution ... But two level hash would raise this limit way up and
>> give more choice of filesystems.

More information about the Info-cyrus mailing list