So the way I see it, the value here is a generic driver that can work with any storage. The downsides: 1. The admin has to manually provision a very big volume and attach it to the Nova and Cinder hosts. Every time a host is rebooted, or introduced, the admin must do manual work. This is one of the things OpenStack should be trying to avoid. This can't be automated without a driver, which is what you're trying to avoid. 2. You lose on performance to volumes by adding another layer in the stack. 3. You lose performance with snapshots - appliances will almost certainly have more efficient snapshots than LVM over network (consider that for every COW operation, you are reading synchronously over the network).
(Basically, you turned your fully-capable storage appliance into a dumb JBOD) In short, I think the cons outweigh the pros. Are there people deploying OpenStack who would deploy their storage like this? Thanks, Avishay On Tue, May 20, 2014 at 6:31 PM, Mitsuhiro Tanino <[email protected]>wrote: > Hello All, > > > > I’m proposing a feature of LVM driver to support LVM on a shared LU. > > The proposed LVM volume driver provides these benefits. > - Reduce hardware based storage workload by offloading the workload to > software based volume operation. > - Provide quicker volume creation and snapshot creation without storage > workloads. > - Enable cinder to any kinds of shared storage volumes without specific > cinder storage driver. > > - Better I/O performance using direct volume access via Fibre channel. > > > > In the attachment pdf, following contents are explained. > > 1. Detail of Proposed LVM volume driver > > 1-1. Big Picture > > 1-2. Administrator preparation > > 1-3. Work flow of volume creation and attachment > > 2. Target of Proposed LVM volume driver > > 3. Comparison of Proposed LVM volume driver > > > > Could you review the attachment? > > Any comments, questions, additional ideas would be appreciated. > > > > > > Also there are blueprints, wiki and patches related to the slide. > > https://blueprints.launchpad.net/cinder/+spec/lvm-driver-for-shared-storage > > https://blueprints.launchpad.net/nova/+spec/lvm-driver-for-shared-storage > > > https://wiki.openstack.org/wiki/Cinder/NewLVMbasedDriverForSharedStorageInCinder > > https://review.openstack.org/#/c/92479/ > > https://review.openstack.org/#/c/92443/ > > > > Regards, > > Mitsuhiro Tanino <[email protected]> > > *HITACHI DATA SYSTEMS* > > c/o Red Hat, 314 Littleton Road, Westford, MA 01886 > > _______________________________________________ > OpenStack-dev mailing list > [email protected] > http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack-dev > >
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