Dovecot + sis problem

[Patrick Cernko]

Hi Michal,

On 06.01.21 00:18, Michał Kiljański wrote:
> Hi,
> My setup is:
> mail_attachment_dir = /var/mail/attachments
> mail_attachment_hash = %{sha512}
> mail_attachment_min_size = 64k
> mail_attachment_fs = sis posix
> 
> Something works - but I expected that is one instance of file, and this 
> file is linked to messages. But here in folder I have got this:
> 
> sudo ls -la /var/mail/attachments/8b/67/
> 
> -rw-rw-rw- 3 buser dovecot 5425280 Jan  5 23:13 
> 8b67b29a73b74ecf48e17e789051602cec13aa78cc01c06c8eee1ca4be7c8e07f700cdc9e9ca0381fa3541bdd4e26289de1d7eee763233dfaa0a200a264e5258-0258913a92f2f45f0d700000035f3f08
> -rw-rw-rw- 1 cuser dovecot 5425280 Jan  5 23:13 
> 8b67b29a73b74ecf48e17e789051602cec13aa78cc01c06c8eee1ca4be7c8e07f700cdc9e9ca0381fa3541bdd4e26289de1d7eee763233dfaa0a200a264e5258-28571b018ff2f45f0c700000035f3f08
> -rw-rw-rw- 3 buser dovecot 5425280 Jan  5 23:13 
> 8b67b29a73b74ecf48e17e789051602cec13aa78cc01c06c8eee1ca4be7c8e07f700cdc9e9ca0381fa3541bdd4e26289de1d7eee763233dfaa0a200a264e5258-50315d3a8ef2f45f0a700000035f3f08
> -rw-rw-rw- 1 auser dovecot 5425280 Jan  5 23:13 
> 8b67b29a73b74ecf48e17e789051602cec13aa78cc01c06c8eee1ca4be7c8e07f700cdc9e9ca0381fa3541bdd4e26289de1d7eee763233dfaa0a200a264e5258-586cdb378ef2f45f07700000035f3f08
> drwxrwsrwx 2 buser dovecot    4096 Jan  5 23:13 hashes
> 
> sudo ls -la /var/mail/attachments/8b/67/hashes/
> 
> -rw-rw-rw- 3 buser dovecot 5425280 Jan  5 23:13 
> 8b67b29a73b74ecf48e17e789051602cec13aa78cc01c06c8eee1ca4be7c8e07f700cdc9e9ca0381fa3541bdd4e26289de1d7eee763233dfaa0a200a264e5258
> 
> 
> What is wrog? How to setup SIS to get one instance of file?

SIS uses hard links. In your example the attachment in 8b/67/hashes/ is 
referenced in 2 other files (aka attached in 2 mails) in the 8b/67/ 
directory. So the data is stored only once on disk but referenced in 3 
directory entries. You can see the refcount in column 3 of ls -l.

Best,
-- 
Patrick Cernko <pcernko at mpi-klsb.mpg.de> +49 681 9325 5815
Joint Administration: Information Services and Technology
Max-Planck-Institute für Informatik & Softwaresysteme

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