[Dovecot] (Single instance) attachment storage

[Timo Sirainen]

On Tue, 2010-08-24 at 11:36 -0500, Mike Abbott wrote:
> > Current implementation checks how many hard links are left for the hash
> 
> I haven't followed all the details and speculation, but this talk of hard-linking makes me wonder how SIS will work with mail stores spread across multiple file systems.

It'll work very nicely. The files are:

attachments/ha/sh/hash-guid, which is a hard link to:
attachments/ha/sh/hashes/hash

So it's always a hard link under a child hashes/ directory. The
attachments/* or attachments/*/* directories can point to any number of
different mount points. Currently it's hard coded to two directory
levels, allowing max. 65536 different dirs/mount points. I don't know if
I should bother making this configurable.