On Tue, Apr 5, 2011 at 01:08, Bron Gondwana <br...@fastmail.fm> wrote: > On Tue, Apr 05, 2011 at 12:28:02AM +0200, Ondřej Surý wrote: >> > I really, really wanted to have BDB able to handle in-place upgrades >> > as well, but I haven't been able to figure out a way. There is an >> > ->upgrade method on databases, but it says it's destructive and can >> > fail - so you can't just run it during the startup process and hope... >> > unless you take a backup first! >> > >> > Eventually my goal is that you can change the DB type in imapd.conf >> > and restart Cyrus, and it will just work. We're nearly there - it >> > will automatically convert between types (by reading the magic from >> > the top of the file) - but it just can't upgrade BDB. Answer that >> > question, and I can give you a 2.4.x release that upgrades magically! >> >> What if you add an option to cyrus-imapd (to all BDB users) which >> would say it can do the in place upgrade. The DB_ENV->upgrade looks >> like it is OK, the only problem is that you need to have backups - and >> that something which can be done either by maintainer script in >> postinst or by administrator - it would also help if there was a >> program which could list all the databases which needs to be >> converted/backuped. >> >> If there was a such option I could easily accomplish some magick with >> depending on dbX.Y-util (where X.Y is the old version of BDB) and >> backup the old database and only after the backup is done (or the >> users say "no" to a backup question because he has the backups already >> or he doesn't care) I could run the cyrus-imapd --do-upgrade (or >> cyrmaster --do-upgrade). That would satisfy both - the safety of the >> databases and the need for seamless upgrade. >> >> How does that sounds? > > Fantastic :) Have a look at the "magic" inside ctl_cyrusdb. One > option (since we default to all non-bdb now) would be to always take > a backup first if it's a BDB file. Then try the upgrade of the backup > file, and if THAT works, then create a new skiplist or BDB file in the > target place. Make startup a bit slow if you insist on using BDB of > course.
You cannot backup (using DB_ENV->archive) before you upgrade, but if you find a way how to call (backend)->init with CYRUSDB_UPGRADE flag and them (backend)->open with same flag, the attached patch should do the trick. (But I advise to review the patch - it's 3AM here...) O. -- Ondřej Surý <ond...@sury.org>
CYRUSDB_UPGRADE.patch
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