On 22 Jun 2006, at 23:53, Daniel O'Connor wrote:
On Friday 23 June 2006 12:17, Seiichirou Hiraoka wrote:
So I want to know the better (or recommend) way to backup
Cyrus-IMAPD /var/imap files to other host without stop
service.
AFAIK the only way to do it properly is to use snapshots on the
file system,
and then use rsync or tar or whatever. If you use rsync the
database will be
inconsistent with itself or other files.
If you're concerned that the databases files be consistent, then the
only way is to cleanly shutdown the processes that have the databases
open. Snapshots will definitely NOT guarantee consistency of the
databases, since consistent database updates can take multiple
writes. Take for example the recent discussion of database
corruption during sudden power lose. Snapshots stop user process
file access very suddenly, not cleanly. Problems created by
snapshots can usually be corrected with reconstruct.
The real question is, what are your backups for? If you're concerned
about recovering mail that the user has deleted, then rsync-ing the
live system is fine. If you want a consistent copy that you could
switch to in the event of a large-scale disaster, then you probably
want to explore application-level replication.
:wes
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