Dear Sunil Thank's a lot for your reply.
I think I maybe wasn't clear enough on one point and you got me wrong. I don't have LVM on top of DRBD but the other way round: OCFS2 -> DRBD -> LVM -> MD-RAID -> physical disk Same on both machines, so do you still think, that's queasy? I have used iSCSI already for some other setup, but wanted to use just 2 single PCs for this setup to have a cluster system with no single point of failure, so I don't see any advantage of using iSCSI in this scenario. You are right with your guess reagrding the o2hb thread. There is one after the system is rebootet and a second one is started, as soon as I mount the snapshot. After unmounting, both are still there, so that appears to be the reason, why I can't remove the snapshot. Is there any (safe) way get rid of it after unmounting? Thank's Armin > -----Original Message----- > From: Sunil Mushran [mailto:sunil.mush...@oracle.com] > Sent: Thursday, March 18, 2010 6:28 PM > To: Armin Wied > Cc: ocfs2-users@oss.oracle.com > Subject: Re: [Ocfs2-users] Can't delete LV snapshot after mounting > > > I am queasy recommending such a setup to anyone. It is one thing to handle > a workload. The problem is about handling user/admin errors. You are > essentially > running a local volume manager that is unaware of the other node. Any > reconfig > that is not coordinated will lead to corruption. Below that you have > drbd which > a fine block device replication solution. But I would personally choose > iscsi > which is a excellent lowcost shared device. Also, does not limit you to > 2 nodes. > The iscsi target in sles is known to be good. Why not just use that and > use drbd > to replicate the device (like emc srdf) for still higher availability. > > Having said that, the 2 you are seeing is not because of the number of > nodes but > because of the hb thread. umount is supposed to stop that hb thread. > Maybe that is > not happening. > > # ps aux | grep o2hb > You should see one when the volume is mounted and not when umounted. > > Sunil > > Armin Wied wrote: > > Hello group! > > > > I'm pretty new to ocfs2 and clustered file systems in general. > > I was able to set up a 2 node cluster (CentOS 5.4) with ocfs2 > 1.4.4 on DRBD > > on top of a LVM volume. > > > > Everything works like a charm and is rock solid, even under heavy load > > conditions, so I'm really happy with it. > > > > However, there remains one little problem: I'd like to do backups with > > snapshots. Creating the snapshot volume, mounting, copying and > dismounting > > works like expected. But I can't delete the snapshop volume after it was > > mounted once. > > > > What I do is: > > > > lvcreate -L5G -s -n lv00snap /dev/vg00/lv00 > > tunefs.ocfs2 -y --cloned-volume /dev/vg00/lv00snap > > mount -t ocfs2 /dev/vg00/lv00snap /mnt/backup > > > > (copy stuff) > > > > umount /mnt/backup > > lvremove -f /dev/vg00/lv00snap > > > > lvremove fails, saying, that the volume is open. Checking with > lvdisplay it > > tells me "# open" is 1. > > And that's the funny thing: After creating the snapshot volume, > # open is 0, > > what's not a surprise. After mounting the volume, # open is 2 - > which is the > > same for the other ocfs2 volume and makes sense to me, as there > are 2 nodes. > > But after unmounting the snapshot volume, the number decreases > to 1, not to > > 0 so LVM consideres the volume still open. > > > > I also tried mounting read only and/or adding "--fs-features=local" to > > tunefs.ocfs2 without success. In the moment I have to reboot > the node to be > > able to remove the snapshot. > > > > So what am I doing wrong? > > > > Thank's a lot for any hint! > > > > Armin > _______________________________________________ Ocfs2-users mailing list Ocfs2-users@oss.oracle.com http://oss.oracle.com/mailman/listinfo/ocfs2-users