That is mostly correct.  Even though you don’t want to write to the LUN, the underlying OS needs to think it can write to it in order to mount it (even if you mount it ro).  Flex Clone solves this issue.  If you don’t have a flex clone license, you should be able to do a lun create –b with the snapshot name and create a snapshot-backed LUN which you could then map to the backup server and do your backup.

 

Either will work.

 

-- Adam Fox
adamfox@netapp.com

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 acquired a cluster of NetApp filers a few months ago with only an iSCSI license (no NFS or CIFS access), intending to use it for data volumes on our Linux and Windows hosts and later for virtualization.  We have one production Gentoo system mounting a data volume from the filer using open-iscsi, and we have several other Gentoo and Ubuntu systems that we would like to configure that way as well.

 

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 "mount LABEL=…" command, perform the backup, unmount the partition, do an iSCSI logout, and delete all the snapshots.

 

Has anyone gotten a setup like this to work?

 

--

David Lee Lambert

Software Developer, Precision Motor Transport Group, LLC

517-349-3011 x223 (work) … 586-873-8813 (cell)

 




--
Romeo Theriault