[linux-lvm] Is cLVM necessary when accessing different logical volumes on a shared iSCSI target?

[Christian Schröder]

Hi list!
I have an iSCSI server (using LIO) which provides one LUN. Two client
machines each connect this same LUN. From the client's perspective, let's
say it shows up as device /dev/sda. I have then in one client created a
partition /dev/sda1 with type 8e (LVM). The partition immediately shows up
in the other client.
After that, I have created a physical LVM volume (pvcreate /dev/sda1) and a
volume group (vgcreate shared /dev/sda1). Note that I have not enabled
cluster mode for this volume group. Again, both the physical volume and the
volume group are immediately visible to the other client.
When I create in one client a logical volume in this volume group, it is
visible to the other client, but it is unavailable. This works in both
directions, i.e. I can create a logical volume in one client or the other,
and it is always visible, but unavailable to the other client.
So far, everything seems to work fine. Now my question is: Is this setup
sufficient or do I need cLVM? I have tried to install cLVM, but had some
problems, because I do not have (and probably do not need?) a cluster
manager.
Could anybody explain when cLVM is needed in general and if it is necessary
for me?

Kind regards,
Christian

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