>From http://cr.yp.to/qmail/faq/reliability.html#backups:
>How do I back up and restore the queue disk?
>
>Answer: You can't.
>
>One difficulty is that you can't get a consistent snapshot of the
>queue while qmail-send is running.
Stop qmail first. And kick off all the users to prevent new messages
from being added to the queue.
>Another difficulty is that messages in the queue must have filenames
>that match their inode numbers.
Run queue-fix after restoring.
>However, the big problem is that backups---even hourly backups!---are
>far too unreliable for mail. If your disk dies, there will be very
>little overlap between the messages saved in the last backup and the
>messages that were lost.
Restoring an old queue will probably result in redelivering some
messages, but it will recover long-undeliverable messages. To me, a
few duplicates are worth it to recover lost messages.
>There are several ways to add real reliability to a mail server.
>Battery backups will keep your server alive, letting you park the
>disk to avoid a head crash, when the power goes out. Solid-state
>disks have their own battery backups. RAID boxes let you replace dead
>disks without losing any data.
Yes, UPS's and disks are cheap.
-Dave
