On an instance of the NetApp Simulator, I
was able to take a snapshot, export it via NFS, create a loopback device based on
the snapshot, and mount the filesystem within it; something like:
Filer> lun
create –b /vol/vol1/luns/lun11 –o noreserve /vol/vol1/luns/lun11_snapforback
Filer> lun
share /vol/vol1/luns/lun11_snapforback read
Linux> mount 10.10.10.23:/vol/vol1
/mnt/netapp-vol1
Linux> losetup
-f /mnt/nasim9-vol1/luns/lun11_snapforback
Linux> kpartx -a
/dev/loop1
Linux> mount /dev/loop1p5
/mnt/lun11-snap
However, as I said, we don’t have an
NFS license; we’ve also heard that NFS performance is poorer than iSCSI
performance. My guess is that some commands like the following ought to
work:
Filer> lun map
/vol/vol1/luns/lun11_snapforback linux-host 3
Linux> iscsiadm
-m discovery --interface eth0 -t st -p 10.10.10.23 --login
Linux> iscsiadm
-m node --interface eth0 -p 10.10.10.23 --login
Linux> mount
/dev/sde /mnt/lun11-snap
When I do that, though, the set of
available SCSI disk devices on the Linux host doesn’t change. Perhaps
this is an open-iscsi limitation instead?
To answer Jack’s questions:
We had Bacula working on the backup-host, and
it doesn’t support NDMP. I don’t think that would be any use for a
LUN (which is just an opaque file to the NetApp), anyway.
Yes, we do want to avoid the overhead of the
backup job on the host, and traffic across two network links when only one
should be necessary. We also want to make as few software changes on the
other hosts as possible.
We don’t have a FlexClone license.
--
David Lee Lambert
Software
Developer, Precision Motor Transport Group, LLC
517-349-3011
x223 (work) … 586-873-8813 (cell)
From: Romeo
Theriault [mailto:romeotheriault@gmail.com]
Sent: Wednesday, November 12, 2008
10:11 AM
To: David L. Lambert; Toasters
Subject: Re: Mounting read-only
snapshots using open-iscsi?
I'm not 100% sure of this, but I don't think you can
map and mount a snapshot itself. (I may be wrong, someone please let me know if
I am) but I believe that you'll need a flexclone license to create a clone of
that particular snapshot and then map the clone to your backup host.
On Wed, Nov 12, 2008 at 8:41 AM, David L. Lambert <dlambert@bmtcarhaul.com> wrote:
[…]
We also have an Ubuntu system connected to a tape
library. We would like to take snapshots of the data-volumes that need to
be backed up, mount those snapshots on the backup host, and do an incremental
backup from the mounted filesystem.
Probably we would partition each LUN with one Linux
partition, and put an ext3 or reiserfs filesystem with a cluster-unique label
on that partition. Then we could take a set of snapshots for the backup,
map all the snapshot LUNs to the backup-host, do iSCSI discovery on the
backup-host, mount each partition (listed in a configuration-file) with a
"
--
Romeo Theriault