-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 dan wrote: > The thing is that it isn't possible to have a perfectly synced remote > copy of a filesystem at every single moment unless they are tied > together in something like raid1 and all writes are syncronos, which > would be murder on performance. Otherwise, there will always be a delay > for the remote sync. at least with a clustered filesystem, the remote > write is immediately queued up so the maximum delay between local or > remote syncing is dicated by the bandwidth between them and not by a set > time and a cron script.
You might also take a look at nbd which can achieve the same sort of thing.... ie, using a RAID1 with one local and one remote member... Personally, I use this (not on backuppc but on a file server) with a RAID5 local member and a remote member which is itself a RAID5 device on the remote machine. Thus I can lose one whole machine, plus one drive, and still not suffer downtime/loss of data. Of course, these days RAID6 might be better, but you can only fit so many disks in a box :( > Alternatively, you could try to raid1 over a remote iSCSI and rely on > the device mapper to handle the syncing on the block level. You could > also use a compressed ssh tunnel to pipe the iSCSI packets between sites > but you should probably put that tunnel in xinet so it is initiated each > time it is needed or reinitiated when it is dropped. > > The issue with that is that a de-sync of the mirror would cause a > rebuild of the mirror set, which would probably sync the entire drive > which would take ages! AFAIK, nbd can solve this problem... though I've not used it extensively since in my case they are both on the same gigabit LAN... BTW, I am not certain that nbd (or any other solution) is the ideal/perfect solution for this or any other problem. They are many way to solve each problem, I just thought I'd add another possible solution. AoE looks interesting, but is restricted to local LAN, I think nbd works over TCP/IP, and of course can be tunnelled over your VPN or ssh tunnel, etc... Regards, Adam - -- Adam Goryachev Website Managers www.websitemanagers.com.au -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.6 (GNU/Linux) Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org iD4DBQFIhsJJGyoxogrTyiURAhEmAJjLMRHl6TTq4s204AZNkSk5pEbfAKC9UfNp JUKi18h5VKKPRII0XH88Uw== =Z3jl -----END PGP SIGNATURE----- ------------------------------------------------------------------------- This SF.Net email is sponsored by the Moblin Your Move Developer's challenge Build the coolest Linux based applications with Moblin SDK & win great prizes Grand prize is a trip for two to an Open Source event anywhere in the world http://moblin-contest.org/redirect.php?banner_id=100&url=/ _______________________________________________ BackupPC-users mailing list [email protected] List: https://lists.sourceforge.net/lists/listinfo/backuppc-users Wiki: http://backuppc.wiki.sourceforge.net Project: http://backuppc.sourceforge.net/
