shouldn't http://www.it.uc3m.es/~ptb/nbd/ with RAID-mirroring be a viable possibility for mailspool & box redundancy?
Regards, Lieven ----- Original Message ----- From: "Vicente Aguilar" <[EMAIL PROTECTED]> To: "Lista qmail-ldap" <[EMAIL PROTECTED]> Sent: Wednesday, January 21, 2004 6:14 PM Subject: Backup server > Hi, fellow admins. > > We'd like to configure a backup of our primary e-mail server, which runs > qmail-ldap 20031101a on a 2 power supply, 2 CPU, 3 eth, RAID-5 SCSI > Intel server (so it should never totally collapse and send all data to > /dev/null, but we're playing being paranoid here). > > The idea is having an as-exact-as-possible replica of the primary server > (same distro, same qmail version, same config...) on a lesser machine, > so that in the event of a total catastrophe on the primary one, we can > manually (or automatically by means of mon, heartbeat or whatever) move > all our mail services to the backups server in a matter of minutes. > > The problem of course lies in keeping all the contents of both servers > synchronized. The LDAP users database isn't a problem thanks to slurpd. > The real problems are: > > - the mail queues > - the mailboxes > > We think that keeping the queues in synch isn't worth it (too complex): > messages in the out-queue for too long will be (likely) discarded anyway > after a copule of days, messages which were just arriving in the moment > of the crash will be re-sent by the other-end servers, and messages just > arrived but still undelivered to the local mailbox... well, I guess > we'll have to cope with that. > > Ideas we have for syncing the mailboxes: > > - running rsync evey n minutes: really easy, but suboptimal (messages > received since the last sync but not downloaded will be lost, messages > downloaded since the last sync before the crash will be downloaded > again). > > - sending all incoming e-mails via qmqp to the secondary server. Optimal > as all incoming mails will be immediately sent to the backup, but how do > we delete mails as the users read them from the primary server? With > rsync again? Will they have the exact same name on both servers? > > - abusing in some way the clustering capabilities in qmail-ldap? Not > suer about this one as I've never used qmail-ldap clustering before. > > > Has any of you something like this running? Any other ideas or > suggestions, besides the classical "NFS server for the mailboxes + n > SMTP/POP heads"? Is this all too complicated, or over-paranoid? > > Any idea will be really appreciated. > > Thanks in advance. > > -- > Vicente Aguilar <[EMAIL PROTECTED]> > Departamento de Sistemas > Tlf.: 965 98 71 92 > > Recursos en la Red, S.L.U. > http://www.renr.es > >
