[Linux-cluster] A few GFS newbie questions: journals, etc

[Fajar A. Nugraha]

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?

>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.

>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.

>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). 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