Papp Tamas <tompos@martos.bme.hu> wrote:
On 04/20/2011 01:47 PM, Sven Hartge wrote:
"du" also accounts for the metadata of the filesystem. With Maildir++ you have many files per directory which causes the directory inode to increase in size. After mails are deleted, the now empty space inside the directory is not reclaimed (at least not in ext2/3/4, I guess, XFS behaves the same) and you see a difference in size, since dovecot only counts the raw size of the mails.
You can test this for yourself: create a directory, place a 100M big file inside and check with "du". Then delete that file, create 10,000 files with 10KB size inside, check with "du", delete the files and check again.
Thank you for your prompt answer.
Why does dovecot count only the raw size? Does this mean, dict quota is not usable with maildirs? Is this true for sdbox also?
In addition to the answer from Timo:
Counting all meta-data is also very unintuitive for the user. Imagine a user with an INBOX containing 200,000 mails. This will result in a _huge_ directory inode for the INBOX folder (about 20MB for XFS). Now he deletes all those mails and expects a quota usage of 0 bytes. But the quota is still at 20MB, because the directory inode has not been reduced by the filesystem.
I guarantee you, you will get numerous support calls.
At least I got them while using filesystem-based quotas.
Grüße, S°
-- Sigmentation fault. Core dumped.