[horde] Problem of slow with server-side sorting

[Roberto Maurizzi]

What file system is used for the Courier maildirs? Ext3 becomes *really*
slow when you have many files in a single directory.
That wouldn't be a big problem for a Cyrus due to its indexes, but for
Courier a filesystem that can access files fast even in directories with
many thousands of files is a must.
You can check if this the cause of your problem manually creating some files
in a dir and then timing commands like cat and rm on those files.

Ciao,
  Roberto