On 25.04.2014 00:40, rammohan ganapavarapu wrote:
One more question, if i have a NAS and i have presented raw LUN to
all my
kvm hosts using iscsi, do i still need to setup clvm or can i just use
iscsi target and cloudstack will use it as primary storage?
I am getting confused with this clvm/shared mount, in cloudstack 4.3
for
kvm hyperviser do i really need to setup clvm or shared mount? instead
can
i directly give storage device ip for primary storage configuration of
course all my kvm hosts can talk to storage and can see iscsi LUN?
Hello,
CLVM is a way of using a network block device (eg iSCSI LUN) in a
cluster-aware manner so you don't end up having multiple nodes using the
same LVM volumes or updating LVM metadata and corrupting it. What it
does is makes all nodes aware of the fact that the volume group on top
of that LUN is used on multiple machines and the cluster software must
be consulted before using it to make sure it's not used elsewhere.
Shared Mount is a powerful option that enables you to use a filesystem
that can be shared between nodes, e.g. you can take the above LUN and
instead of "formatting" as CLVM you can put OCFS2 or GFS2 on top of it
and use it like a clustered filesystem. Be advised this will probably be
more complex to set up than CLVM and also less performant.
Another example of using Shared Mount is mounting a GlusterFS volume as
data stor, or CephFS, or XtreemFS or pretty much any network/cluster
filesystem out there, if KVM can run off a qcow2 file off it then it's
good enough for Cloudstack.
How you would do it in practice is very simple:
- on all hypervisors mount the desired filesystem/mounpoint in a path,
e.g. /mnt/glusterfs, make sure it's writable etc
- add the Primary Storage as Shared Mount point and when asked about
the path input "/mnt/glusterfs"
HTH
Lucian
--
Sent from the Delta quadrant using Borg technology!
Nux!
www.nux.ro
