Note: "permalinks" may not be as permanent as we would like,
direct links of old sources may well be a few messages off.
Hello list,
I have a Heartbeat test configuration with two nodes (nodeA active,
nodeB standby for warm failover) and DRBD for data synchronisation over
GBit Ethernet. DRBD is on top of LVM (LVM is on top of Raid-5), because
I want use the LVM snapshot facility to make periodic backups of the
block devices controlled by DRBD (data on /dev/nb0: mysql, ldap,
apache). So, my questions (nodeA is primary for DRBD):
1.) What I have to bear in mind when making a snapshot of the drbd
device /dev/nb0 on nodeA? How would I do this without breaking drbd
("[...] never [...] access the underlying device directly" from Some
Do's and Dont's, DRBD Article in Linux Mag)?
2.) Can I stop drbd (/dev/nb0) on nodeA (without the result that nodeB
becomes primary for drbd), do the snapshot, save the snapshot data,
destroy the snapshot again (snapshot data is already saved), put the
saved and tar'ed snapshot data on a second drbd device (/dev/nb1), start
drbd, so a sync between nodeA and nodeB will be started. The result is:
nodeA synch all the data on /dev/nb0 written during the snapshot (were
drbd was down) and the data on /dev/nb1 (the saved and tar'ed snapshot
file) with nodeB. nodeB has then the same data on /dev/nb0 (for mysql,
ldap, apache) and on /dev/nb1 (the snapshot backup), too. This snapshot
thing should run as Heartbeat service, later (if it makes sense).
Does this sounds like a good way? Any hints or ideas are most welcome!
--
Best regards,
Andreas Semt