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Re: [Xen-users] iscsi vs nfs for xen VMs

On Wed, Jan 26, 2011 at 3:05 PM, Christian Zoffoli <czoffoli@xxxxxxxxxxx> wrote:
> d) NFS is slow ...NFS over RDMA is fast but freebsd has no open/official
> infiniband stack

ZFS is slow for image files (unless you get a big honking NFS
appliance); but in this case it's serving files.

> e) consistent snapshots are very different from backuping only files.

in most cases, inconsistencies arise from long-open files and
non-flushed caches/buffers on the guest.

when serving images, restoring from such a backup is equivalent to a
hard crash of the filesystem; at least would require a journal replay,
possibly with lost data.  But, this is not the case here, because NFS
isn't serving images.

the other issue i know is about databases.  just restoring the stored
data won't get you a consistent system.  Definitely, backup databases
'from inside', using database tools.


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