ok so lvm, md are local to a node. It should be stopping on umount. If not, try to shut it manually.
To see the number of refs, do: # ocfs2_hb_ctl -I -d /dev/sdX o2cb To decrement a ref, do: # ocfs2_hb_ctl -K -d /dev/sdX o2cb The fs decrements using UUID. # ocfs2_hb_ctl -K -u UUID o2cb To find the uuid, do: tunefs.ocfs2 -Q "%U\n" /dev/sdX Armin Wied wrote: > 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
