Is It possible to backup an iSCSI drive via Time Machine?

[matthewpomar]

Hi folks.

It seems ATTO folks have developed a iSCSI Initiator for current macOS versions. This solves a lot of problems for me, but I am thinking about backups. The iSCSI volume will be backup-up on the server, but it would also be nice to have a separate copy of the data in a different format (Time Machine) so that I can restore from there if I needed to as well.

So, does Time Machine backup iSCSI drives?

 

[gilby101]

So, does Time Machine backup iSCSI drives?

No one else has answered, so:

I have no first hand evidence, but I very much doubt it. Time Machine only ever offers to backup from directly attached drives - it does not offer to backup from SMB or NFS. I can find no web search reference to TM backup from iSCSI.

But I would expect Carbon Copy Cloner to do what you want. CCC successfully does backups from SMB and NFS so I am guessing that iSCSI sources will work too. But you would need to test it. And so long as your destination is AFPS, it will keep snapshots (rather like TM does). You may run into conflicts with case-sensitivity.

Even if the TM solution does work, I would recommend against it. TM does not give you much flexibility and doesn't like having source disks which might not be present all the time. Even with all directly attached source drives I prefer to a) keep TM just for my boot volume and b) create CCC jobs for each non-boot source volume.

 

[ChrisA]

It should work. if iSCSI looks like a directly attached disk.

I see the above suggestion to just "clone the drive" but while that is conceptually simple it is inefficient. With iSCSI you will be able to put an APFS file system on the iSCSI drive and TM will be able to find and backup ONLY the changed data and it will run hourly. So you lose at most one hour of data.

In any case, as long as you keep 3 copies of the data on 3 different physical media and at the same time keep the media in at least 2 different geographical locations, you are OK for most cases. The details matter less than those numbers. For business-critical data, you might change numbers from "3 and 2" to "4 and 3".

 

[gilby101]

I see the above suggestion to just "clone the drive" but while that is conceptually simple it is inefficient. With iSCSI you will be able to put an APFS file system on the iSCSI drive and TM will be able to find and backup ONLY the changed data and it will run hourly. So you lose at most one hour of data.

If that is referring to my post, CCC does not just "clone the drive". Like TM, if the destination disk is APFS format, it makes snapshots just like TM. CCC is functionally very like TM but with more configuration choices.

I didn't know that iSCSI mounts like a DAS. That makes it easier for the OP.