On 24.1.2011, at 15.52, Javier de Miguel Rodrí guez wrote: > - One of the main advantages (speed wise) of dbox over maildir is that > index files are the only storage for message flags and keywords. What happens > when we want to recover some messages from backup? With maildir we can > rebuild message indexes, but I am not sure about dbox. Should we also restore > "old indexes" and merge with the "new indexes" in order to restore the > deleted messages?
The intended way to restore stuff is to either restore the entire dbox to a temp directory, or at least all the important parts of it (indexes + the files that contain the wanted mails) and then use something like: doveadm import sdbox:/tmp/restoredbox "" savedsince 2011-01-01 > - The previous question applies to sdbox and mdbox. In the case of mdbox, > we can configure rotation of files using /mdbox_rotate_size/ . We would like > to rotate daily, not based in size (our users ask us for yesterday's backup). > How can we accomplish this? mdbox_rotate_interval = 1d But note that that doesn't guarantee that there will be only one file. Even if you set mdbox_rotate_size to 10 GB or something (or I think 0 makes it unlimited, not sure), it's possible that two files will be created if mails are being saved at the same time. mdbox never waits for locks when writing to a file, instead it'll just use another file or create a new one. Anyway, if it's not a big deal restoring the user's entire mailbox temporarily you can restore only yesterday's mails by giving proper search query parameter to doveadm import. > We have now 17.000.000 messages in our maildir, almost 1.5 TB (zlib > compresssion enabled). Our backup time with bacula is rather bad: 24 hours > for a full backup, most of the time the backup is busy fstat'ing all those > little messages. In case of Maildir there's no point in fstating any mail files. I'd guess it should be possible to patch bacula to not do that. > We think that mdbox can help us in this. Does anybody has good experiences > migrating from maildir->mdox in "large" enviroments? What about mdox > performance & reliability? I haven't recently heard of corruption complaints about mdbox.. Previously when there were those, I didn't hear of complains about losing mails or anything, so that's good :)
