sis deduplication broken from 2.2.16 upwards
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Hi,
sis attachment deduplication is broken in 2.2.16 upwards. It is caused by this commit. https://github.com/dovecot/core/commit/664bf3e236c214aee86294483c379e4fa66c2...
in src/lib-fs/fs-sis.c function fs_sis_try_link() is comparation of inodes of hash files. Because fs_stat() after that commit use fstat() on open fd of temporary file instead of stat on filename. But that temporary file has differnt inode.
It not cause any corruption but it will not save any space. Because every duplicate attachment will be in separate file.
[ Ohodnotte kvalitu mailu: https://www.nicereply.com/websupport/4afafd34 ]
Pavel Stano | Troubleshooter
http://WebSupport.sk *** BERTE A VYCHUTNAVAJTE ***
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On 08 Mar 2016, at 01:50, Pavel Stano stanojr@websupport.sk wrote:
sis attachment deduplication is broken in 2.2.16 upwards. It is caused by this commit. https://github.com/dovecot/core/commit/664bf3e236c214aee86294483c379e4fa66c2...
in src/lib-fs/fs-sis.c function fs_sis_try_link() is comparation of inodes of hash files. Because fs_stat() after that commit use fstat() on open fd of temporary file instead of stat on filename. But that temporary file has differnt inode.
It not cause any corruption but it will not save any space. Because every duplicate attachment will be in separate file.
Thanks, fixed: https://github.com/dovecot/core/commit/3b39022ea0513363241cf852b7d454c841584...
On 3/9/2016 9:02 PM, Timo Sirainen tss@iki.fi wrote:
On 08 Mar 2016, at 01:50, Pavel Stano stanojr@websupport.sk wrote:
sis attachment deduplication is broken in 2.2.16 upwards. It is caused by this commit. https://github.com/dovecot/core/commit/664bf3e236c214aee86294483c379e4fa66c2...
in src/lib-fs/fs-sis.c function fs_sis_try_link() is comparation of inodes of hash files. Because fs_stat() after that commit use fstat() on open fd of temporary file instead of stat on filename. But that temporary file has differnt inode.
It not cause any corruption but it will not save any space. Because every duplicate attachment will be in separate file.
Thanks, fixed: https://github.com/dovecot/core/commit/3b39022ea0513363241cf852b7d454c841584...
So, after the fix is applied, does dovecot silently delete the duplicated files, or is there a command that needs to be run manually?
On 11 Mar 2016, at 02:37, Charles Marcus CMarcus@Media-Brokers.com wrote:
On 3/9/2016 9:02 PM, Timo Sirainen tss@iki.fi wrote:
On 08 Mar 2016, at 01:50, Pavel Stano stanojr@websupport.sk wrote:
sis attachment deduplication is broken in 2.2.16 upwards. It is caused by this commit. https://github.com/dovecot/core/commit/664bf3e236c214aee86294483c379e4fa66c2...
in src/lib-fs/fs-sis.c function fs_sis_try_link() is comparation of inodes of hash files. Because fs_stat() after that commit use fstat() on open fd of temporary file instead of stat on filename. But that temporary file has differnt inode.
It not cause any corruption but it will not save any space. Because every duplicate attachment will be in separate file.
Thanks, fixed: https://github.com/dovecot/core/commit/3b39022ea0513363241cf852b7d454c841584...
So, after the fix is applied, does dovecot silently delete the duplicated files, or is there a command that needs to be run manually?
You'd have to do it manually in some way. A script that does something like:
Go through all attachment directories and for each file:
- Sort files by filename
- Identify that files A and B the same (beginning of the filename begins with same hash), but have a different inode
- ln A B.tmp && mv B.tmp B
Am 11.03.2016 um 01:56 schrieb Timo Sirainen:
On 11 Mar 2016, at 02:37, Charles Marcus CMarcus@Media-Brokers.com wrote:
On 3/9/2016 9:02 PM, Timo Sirainen tss@iki.fi wrote:
On 08 Mar 2016, at 01:50, Pavel Stano stanojr@websupport.sk wrote:
sis attachment deduplication is broken in 2.2.16 upwards. It is caused by this commit. https://github.com/dovecot/core/commit/664bf3e236c214aee86294483c379e4fa66c2...
in src/lib-fs/fs-sis.c function fs_sis_try_link() is comparation of inodes of hash files. Because fs_stat() after that commit use fstat() on open fd of temporary file instead of stat on filename. But that temporary file has differnt inode.
It not cause any corruption but it will not save any space. Because every duplicate attachment will be in separate file.
Thanks, fixed: https://github.com/dovecot/core/commit/3b39022ea0513363241cf852b7d454c841584...
So, after the fix is applied, does dovecot silently delete the duplicated files, or is there a command that needs to be run manually?
You'd have to do it manually in some way. A script that does something like:
Go through all attachment directories and for each file:
- Sort files by filename
- Identify that files A and B the same (beginning of the filename begins with same hash), but have a different inode
- ln A B.tmp && mv B.tmp B
This functionality is how it works in sis-queue correct?
Wouldn't it be nice to adopted doveadm sis deduplicate to handle this?
regards
-- Harald Leithner
ITronic Wiedner Hauptstraße 120/5.1, 1050 Wien, Austria Tel: +43-1-545 0 604 Mobil: +43-699-123 78 4 78 Mail: leithner@itronic.at | itronic.at
On 3/10/2016 7:56 PM, Timo Sirainen tss@iki.fi wrote:
On 11 Mar 2016, at 02:37, Charles Marcus CMarcus@Media-Brokers.com wrote:
On 3/9/2016 9:02 PM, Timo Sirainen tss@iki.fi wrote:
On 08 Mar 2016, at 01:50, Pavel Stano stanojr@websupport.sk wrote:
sis attachment deduplication is broken in 2.2.16 upwards. It is caused by this commit. https://github.com/dovecot/core/commit/664bf3e236c214aee86294483c379e4fa66c2...
in src/lib-fs/fs-sis.c function fs_sis_try_link() is comparation of inodes of hash files. Because fs_stat() after that commit use fstat() on open fd of temporary file instead of stat on filename. But that temporary file has differnt inode.
It not cause any corruption but it will not save any space. Because every duplicate attachment will be in separate file. Thanks, fixed: https://github.com/dovecot/core/commit/3b39022ea0513363241cf852b7d454c841584... So, after the fix is applied, does dovecot silently delete the duplicated files, or is there a command that needs to be run manually? You'd have to do it manually in some way. A script that does something like:
Go through all attachment directories and for each file:
- Sort files by filename
- Identify that files A and B the same (beginning of the filename begins with same hash), but have a different inode
- ln A B.tmp && mv B.tmp B
Ugh... ok thanks, but it seems like that would be much safer as a doveadm command...
On 11.03.16 3:56, Timo Sirainen wrote:
On 11 Mar 2016, at 02:37, Charles Marcus CMarcus@Media-Brokers.com wrote:
On 3/9/2016 9:02 PM, Timo Sirainen tss@iki.fi wrote:
On 08 Mar 2016, at 01:50, Pavel Stano stanojr@websupport.sk wrote:
sis attachment deduplication is broken in 2.2.16 upwards. It is caused by this commit. https://github.com/dovecot/core/commit/664bf3e236c214aee86294483c379e4fa66c2...
in src/lib-fs/fs-sis.c function fs_sis_try_link() is comparation of inodes of hash files. Because fs_stat() after that commit use fstat() on open fd of temporary file instead of stat on filename. But that temporary file has differnt inode.
It not cause any corruption but it will not save any space. Because every duplicate attachment will be in separate file.
Thanks, fixed: https://github.com/dovecot/core/commit/3b39022ea0513363241cf852b7d454c841584...
So, after the fix is applied, does dovecot silently delete the duplicated files, or is there a command that needs to be run manually?
You'd have to do it manually in some way. A script that does something like:
Go through all attachment directories and for each file:
- Sort files by filename
- Identify that files A and B the same (beginning of the filename begins with same hash), but have a different inode
- ln A B.tmp && mv B.tmp B
I've also found that many of /hashes/ directories have missed.
# ll /tank1/vmail/attachments/1f/1f total 3300 -rw------- 1 vmail vmail 403976 12 ноя 00:20 1f1f504c582600a2af94b39c088692aba714fe72-c53b9e1508b14356797d0100d09efc50 -rw------- 1 vmail vmail 403976 12 ноя 00:20 1f1f504c582600a2af94b39c088692aba714fe72-c93b9e1508b14356797d0100d09efc50 -rw------- 1 vmail vmail 403976 12 ноя 00:20 1f1f504c582600a2af94b39c088692aba714fe72-f2a777181eb14356807d0100d09efc50 -rw------- 1 vmail vmail 403976 12 ноя 00:20 1f1f504c582600a2af94b39c088692aba714fe72-f31a5e2917b143567e7d0100d09efc50 -rw------- 1 vmail vmail 2582016 3 ноя 00:20 1f1f97880e8cddc2dfe3c4ad2654b9da937226b7-94c53d358bd33756d6140000d09efc50
Is it related to the same bug or there is another issue? Is it safe to delete attachment files if there is no file with the same hash in the /hashes/ directory or there is no /hashes/ directory at all?
On 11.03.2016 3:56, Timo Sirainen wrote:
So, after the fix is applied, does dovecot silently delete the duplicated files, or is there a command that needs to be run manually?
You'd have to do it manually in some way. A script that does something like:
Go through all attachment directories and for each file:
- Sort files by filename
- Identify that files A and B the same (beginning of the filename begins with same hash), but have a different inode
- ln A B.tmp && mv B.tmp B
The problem turned out to be a bit more complicated than that.
Finally a came up with that script: https://github.com/moisseev/doveadm-tools/blob/master/bin/dsisck
It assumes Dovecot should not run.
participants (5)
-
Alexander Moisseev
-
Charles Marcus
-
Harald Leithner
-
Pavel Stano
-
Timo Sirainen