[Linux-cluster] is necesary to to build GFS on top of LVM ?

[David Sparks]

> I was wondering why in the docs and examples the GFS
> filesystem is build on top of a lv "partition" ?
> I can understand that if I build the GFS in a direct
> scsi attached storage because is not easy to grow the
> "device" without destroy the data but the same apply
> in an SAN enviroment?
> We have here a EMC SAN, where is relative easy to grow
> a LUN, so can we skip the LVM layer and build the GFS
> filesystem directly over the emcpower device ? 

A variation of this question, what about creating GFS directly on the
block device (ie /dev/sdb) instead of creating partitions (ie /dev/sdb1)?

When increasing a filesystem, this removes the step of increasing the
partition size, which is usually the scariest part (because you are
usually deleting the partition table, and recreating it with the same
starting layout, hoping that your existing filesystem will be intact).

Does parted support GFS?  It doesn't support XFS which is another FS I
am using.  So I asked myself, why bother creating a partition table at
all?  I have been running the fs directly on the block device for some
time now without issue (XFS, haven't tried GFS).

A setup like this has a weakness in that people who aren't familiar with
it may come along with fdisk and corrupt the disk by creating a
partition table on it.  You might rename fdisk as a basic preventative.

ds





> 
> there is any advantage of using LVM in this scenario?
> 
> thanks in advance
> roger