Le 10/07/2012 19:11, Tommi Virtanen a écrit :
On Tue, Jul 10, 2012 at 9:39 AM, Yann Dupont <Yann.Dupont@xxxxxxxxxxxxxx> wrote:
The cluster mechanism was never intended for moving existing osds to
other clusters. Trying that might not be a good idea.
Ok, good to know. I saw that the remaining maps could lead to problem, but
in 2 words, what are the other associated risks ? Basically If I use 2
distincts config files,
with differents & non-overlapping paths, and different ports for OSD, MDS &
MON, we basically have 2 distincts and independant instances ?
Fundamentally, it comes down to this: the two clusters will still have
the same fsid, and you won't be isolated from configuration errors or
Ah I understand. This is not the case : see :
root@chichibu:~# cat /CEPH/data/osd.0/fsid
f00139fe-478e-4c50-80e2-f7cb359100d4
root@chichibu:~# cat /CEPH-PROD/data/osd.0/fsid
43afd025-330e-4aa8-9324-3e9b0afce794
(CEPH-PROD is the old btrfs volume ). /CEPH is new xfs volume,
completely redone & reformatted with mkcephfs. The volumes are totally
independant :
if you want the gore details :
root@chichibu:~# lvs
LV VG Attr LSize Origin Snap% Move Log
Copy% Convert
ceph-osd LocalDisk -wi-a- 225,00g
mon-btrfs LocalDisk -wi-ao 10,00g
mon-xfs LocalDisk -wi-ao 10,00g
data ceph-chichibu -wi-ao 5,00t <- OLD btrfs,
mounted on /CEPH-PROD
data xceph-chichibu -wi-ao 4,50t <- NEW xfs, mounted
on /CEPH
leftover state (such as the monmap) in any way. There's a high chance
that your "let's poke around and debug" cluster wrecks your healthy
cluster.
Yes I understand the risk.
By the way, is using 2 mon instance with different ports supported ?
Monitors are identified by ip:port. You can have multiple bind to the
same IP address, as long as they get separate ports.
Naturally, this practically means giving up on high availability.
The idea is not just having 2 mon. I'll still use 3 differents machines
for mon, but with 2 mon instance on each. One for the current ceph, the
other for the old ceph.
2x3 Mon.
Cheers,
--
Yann Dupont - Service IRTS, DSI Université de Nantes
Tel : 02.53.48.49.20 - Mail/Jabber : Yann.Dupont@xxxxxxxxxxxxxx
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