On Tuesday 05 July 2005 11:04 pm, Fajar A. Nugraha wrote: > Jason Lanclos wrote: > > >>>You shouldn't even need CLVM if you don't intend to muddle with > >>>partitions or cross-mount the file systems. You'll lose resizing, but > >>>in doing so, your clients no longer need to be cluster participants. > >>> > >>> > > > >CLVM is cool, but its pretty much useless until LVM2 actually implements > >pvresize or a pvextend. > > > What's wrong with vgextend? Nothings wrong with vgextend.. but its useless when i want to extend a pv. > > >One of the main advantages of having a SAN is being > >able to add space to a volume (LUN) Currently when we expand a volume on > >the san, we have to unmount the filesystem, rescan the LUNs, then run fdisk > >on that volume, delete the partition entry, and recreate it to use all the > >space.. then at that point we can run ext2online / gfs_grow to resize the > >filesystem. > > > > > > > A simpler method will be create a NEW LUN, scan it, pvcreate, add it to > existing VG with vgextend, and extend your volume lvextend. At least you > don't have to mess with existing partitions. Ok.. what happens when you reach the max LUNs or max partitions??? And I can only imagine the administration nightmare it would be to manage with several volumes spread over multiple LUNs. The whole point of a SAN is to simplify management of data storage. And what about copy/swap? Spreading a volume over multiple LUNs would make using this feature of the SAN impossible / very dangerous to do while volumes are mounted. So.. One Volume, One LUN, One partition is the easiest way. There are prolly a thousand different ways to "make it work", but I wouldn't consider that part of the whole "Red Hat Enterprise Linux" concept. I know I'm not the 1st person to run into this issue.. so rather than having numerous work arounds, why not just implement pvresize/pvextend to do this? https://www.redhat.com/archives/linux-lvm/2003-July/msg00038.html Oh.. and there's already a man page for it.. even though its not implemented in LVM2: http://mandoc.etopian.net/man/linux/8/pvresize And a work around that I'd be reluctant using on a production system: http://www.redhat.com/archives/linux-lvm/2004-December/msg00049.html > > >I would be VERY nice if pvresize / pvextend existed, that way one could expand > >the volume on the SAN, > > > My IBM SAN can't expand exisiting volume on the SAN. It's not like I > need it though. The above solution works better. XioTech Magnitude expands volumes with no problem.. Its one of the reasons we chose it for our SAN. > > >rescan LUNs on each cluster member, run pvresize / > >pvextend, run lvextend and then gfs_grow and call it a day. > > > > > > > My only problem (for now) is I can't rescan LUNs without removing HBA > modules (thus unmounting filesystems or restarting the server). I'm not sure if it will work with your FC card, but I've used the following script a few times with a qlogic card and it worked. http://www.fifi.org/cgi-bin/man2html/usr/share/man/man8/rescan-scsi-bus.sh.8.gz > If you > can rescan LUNs online, it's a simple method of pvcreate, vgextend, > lvextend, gfs_grow, and call it a day. > > >I mentioned this at the RedHat summit, and got a few puzzled looks, > > > I wonder why :-D > > Regards, > > Fajar > > -- > > Linux-cluster@xxxxxxxxxx > http://www.redhat.com/mailman/listinfo/linux-cluster > -- Jason Lanclos Systems Administrator Red Hat Certified Engineer Southeastern Louisiana University -- Linux-cluster@xxxxxxxxxx http://www.redhat.com/mailman/listinfo/linux-cluster
