LUN Backup with block-based LUNs per command line

iSCSI related applications
sebneu
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LUN Backup with block-based LUNs per command line

Postby sebneu » Wed Oct 31, 2018 7:17 pm

Hi

we use the qnap NAS TS 879 PRO only for providing iSCSI targets which are connected to a linux machine.
From the linux machine we trigger a readonly snapshot of a lun (per ssh) which is attached to a second iSCSI target. This is attached to a second linux machine. This linux machine is attached to a tape library where all data from the iSCSI LUN is saved. After the backup has finished a second ssh command deletes the LUN snapshot. (see manual System Settings - Storage Manager - iSCSI - LUN Backup - Managing LUN Backup/Restore/Snapshot by Command Line)

Now I would like to setup a new Storage pool with fresh disk and benefit from the new block-based LUNs, since the QTS/Support pages recommend them:
"File-based LUN are available for legacy support. It is highly recommended to use block-based LUN to benefit all the new features provided by QTS 4.0. You can refer to the user manual to see a details list of supported features."
Our setup which is up and runnig for years apparently works with file-based LUNs only - block-based LUNs are not listed in the "iSCSI - LUN Backup - Create a Job - Create a LUN Snapshot" Dialog.

The only way I found so far to achieve our setup with block-based luns is:
- take a snapshot of the filebase lun
- clone the snapshot
- attach the clone to a second target

But I haven't found a way to do this without manual interaction with the qts and I am not sure at all what the clones are/do. Do they reserve extra space? Can they be scheduled? And why do I have to clone a snapshot? Even if that's possible I am not sure for how long snapshots should exists, since I don't know how long the tape library takes to save the data. Taking a snapshot per ssh was so easy! How can I do that with block-based LUNs? Any other suggestion?

Regards and thank you for your help!
sebneu

---
NAS: QNAP TS 879 Pro
Firmware 4.2.2

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storageman
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Re: LUN Backup with block-based LUNs per command line

Postby storageman » Wed Oct 31, 2018 7:49 pm

4.3.5.0728 build 20181013 is latest
Clearly you clone a snapshot so as to not overwrite the original data.
Did you look at Snapshot Replication? You can create a schedule and keep a max no of snapshots.
Taking snapshots on block based thick LUNs need plenty of space.

sebneu
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Re: LUN Backup with block-based LUNs per command line

Postby sebneu » Wed Oct 31, 2018 8:19 pm

Hi storageman

thank you for your reply

storageman wrote:4.3.5.0728 build 20181013 is latest

I am aware that I am not using the latest build. If the 4.3 build offers what i want I will happily migrate.

storageman wrote:Clearly you clone a snapshot so as to not overwrite the original data.

When I take a snapshat and delete it after whatever I want to do with the data, I will not overwrite the data. That's the difference between delete and revert. But what is clone?

storageman wrote:Did you look at Snapshot Replication? You can create a schedule and keep a max no of snapshots.

I thought Snapshot Replication is more or less a QNAP only feature. Maybe I am wrong. How would I setup a normal linux machine to accept the lun? I am not sure if this is the way to go....

storageman wrote:Taking snapshots on block based thick LUNs need plenty of space.

Does this mean you would recommend the legacy file-based LUNs? Does that use less space? As I said - I am only interessted in read only snapshots which will be deleted after all data is written to tapes.

Thanks!

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storageman
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Re: LUN Backup with block-based LUNs per command line

Postby storageman » Wed Oct 31, 2018 10:26 pm

I think you should test it.
Nothing to stop you sending it to itself then backing it up on a rotation basis (say max 2 snapshots).

sebneu
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Re: LUN Backup with block-based LUNs per command line

Postby sebneu » Wed Oct 31, 2018 11:11 pm

I tested it.
I manged to create a snapshot but not to attach that as a LUN to a iSCSI target. So I cannot attach that to the linux machine. It's only available at the QNAP.
So, there is no success there.

And still, if that would have been successfull, that would mean manual interaction which I definitely not want.

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storageman
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Re: LUN Backup with block-based LUNs per command line

Postby storageman » Thu Nov 01, 2018 12:03 am

LUN backup will do thick block LUNs too.
You can send them to NFS/SMB remote share.

sebneu
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Re: LUN Backup with block-based LUNs per command line

Postby sebneu » Thu Nov 01, 2018 5:17 pm

No block-based LUN is advertised under iSCSI backup - LUN snapshot. might be a bug in my build?

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storageman
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Re: LUN Backup with block-based LUNs per command line

Postby storageman » Thu Nov 01, 2018 5:31 pm

4.3.4 0695 allows it

sebneu
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Re: LUN Backup with block-based LUNs per command line

Postby sebneu » Thu Nov 01, 2018 6:07 pm

I'll try that....
Thanks

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storageman
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Re: LUN Backup with block-based LUNs per command line

Postby storageman » Thu Nov 01, 2018 6:55 pm

sebneu wrote:I'll try that....
Thanks


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sebneu
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Re: LUN Backup with block-based LUNs per command line

Postby sebneu » Mon Nov 05, 2018 11:48 pm

Could you please check for me, if the block-based LUN is available at "Create a LUN Snapshot" and not "Back up an iSCSI LUN". I checked this in the QTS demo at the QNAP homepage but that one does not even have the whole LUN Backup item in the side menu.
In my version the block-based LUN is available in "Back up an iSCSI LUN" but is not under "Create a LUN Snapshot". I don't want to upgrade the firmware to 4.3.5 (as the demo on the QNAP hp) and after that our whole setup does not work anymore, since the whole item is missing... That risk is too high...

Your help is highly appreciated!
Thanks

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storageman
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Re: LUN Backup with block-based LUNs per command line

Postby storageman » Tue Nov 06, 2018 12:18 am

Both are there LUN backup and snapshot of a thick LUN.


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