On 05/04/12 17:42, Craig Sanders wrote:
Overall ganeti is really nice, but it feels like drbd has some missing pieces that would help in debugging issues.
i'm wondering if iscsi kind of obsoletes drbd, and if mdadm raid1 over two iscsi exports would be better than drbd.
Oooh, no, don't do that. We've tried it. It didn't work out. It sounds like a good idea at first, but every time you need to reboot one or other of the iscsi targets (eg. for kernel updates or suchlike) you'll need to rebuild the RAID array, and the performance of that over ethernet blows.
part of my curiosity is due to the fact that i prefer zfs to lvm, and iscsi ... when i get time i intend to experiment with ganeti and see if i can come up with a zfs+iscsi+mdadm storage module for it as an alternative to lvm+drbd.
this would also allow skipping the io-hogging mdadm check (replaced with a weekly or monthly zpool scrub).
I'd be interested to hear your experiences of that, if you get it up and running. -Toby