[DRBD-user] drbd or rsync?
sallyanne.edwards at googlemail.com
Wed Apr 8 18:38:54 CEST 2009
> A crucial factor is wether you can tolerate stale data. Running rsync
> periodically will probably result in not-quite-uptodate replication when the
> storm troopers come rushing in and cut your power. If that is not a concern,
> eg. because your data doesn't change all that often, or you simply don't care
> about a few lost updates, then rsync is IMHO simpler to set up.
> In contrast, DRBD does real replication. Depending on your link/network
> quality and the chosen protocol you can guarantee that local writes are only
> considered complete if the remote side also has completed.
Maybe it is a re-incarnation of executive order 6102, to melt down the
servers for their gold content?
Anyhow, provided the bandwidth is sufficient, I prefer the DRBD
option. However, will the backups be successful, if the backup drive
is attached to the secondary? Most of what I've read suggests that
you shouldn't even mount the secondary in read-only mode (although
maybe an LVM snapshot can be mounted for taking a backup).
For databases, I intend to dump them to text files at least an hour
before attempting to make a backup of the secondary. This gives me
something to fall back on if the raw files are not in a consistent
state on the secondary.
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