SOLVED Cold Backup Solutions

[Davvo]

Currently my backup solution consists in quite a few heterogeneous 2.5'' drives ransacked from laptops or simple external use ones; I do not trust this option and want to reduce the number of drives as well as use ZFS replycation in order to assure the integrity of my data: I want to trust my cold (offsite) backup!

Currently, the maximum usable space of my data pool is [less then] 5TB; I want to have at least 3 TB of space in this drive, and I was thinking of increasing the copies parameter in order to increase the resiliency of this extreme solution (btw, haven't actually verified this is compatible with zfs replication), so at least 6 TB.

The question is, which drive should I buy? Assuming SMR is plague, should I just buy a standard NAS drive since from a brief search it appears the only drives of such sizes that use CMR are NAS lines? I plan to put it into a 3.5'' enclosure with a USB adapter and manually import and export the pool monthly.

Have I missed something? Are there better alternatives? Please do note that I do not have the option of a second machine as offsite replication target, and the prices for online zfs storage make my sweat.

 

[winnielinnie]

Assuming SMR is plague, should I just buy a standard NAS drive since from a brief search it appears the only drives of such sizes that use CMR are NAS lines? I plan to put it into a 3.5'' enclosure with a USB adapter and manually import and export the pool monthly.

Any external 8TB (or larger) Western Digital drive will be de facto CMR. You won't need to purchase an extra enclosure either. They cost less than an equivalent Red Plus or Red Pro drive.

I was thinking of increasing the copies parameter in order to increase the resiliency of this extreme solution

This won't provide resiliency against a drive failure.



If feasible, for these "once a month" backups, you can purchase 2 external powered drives (e.g, WD Elements 8TB+) and create a mirror vdev for the backup pool. Plug them in together, disconnect them together. (As separate drives in separate ports; not in a "caddy".)

The first (full) replication might take a while, but it shouldn't be an issue after that.

 

[Etorix]

Any ZFS parameter is compatible with ZFS replication. Copies=2 just means you'll wait twice as long to complete since everything will be written twice. And you'll need a 10 TB drive or larger to backup 5 TB.
Just any drive should do, in particular external USB drives which you won't even bother to shuck for this application. SMR might not even be "plague" in this application because the issue with ZFS is when resilvering, especially raidz# arrays, but you won't resilver an external backup on a single-drive pool. SMR, tough, sucks at long continuous writes, and that's precisely what you'll be doing when backing up.

How to: Backup to local disks

How to: Backups to local disks Overview: This subject comes up often enough that I thought I would start a post of how I do it. Specifically I back up my TrueNAS to a hot-inserted, locally attached disk, then when done, hot-remove and take...

www.truenas.com

 

[Etorix]

This won't provide resiliency against a drive failure.

But this will protect against developing bad sectors and UREs. The purpose is to have a cold (and off-site?) backup to restore from, not to make the backup itself super-resilient.

With two drives or more, I'd rather do rotating backups than setting up a mirror through USB.

 

[Davvo]

Any external 8TB (or larger) Western Digital drive will be de facto CMR. You won't need to purchase an extra enclosure either. They cost less than an equivalent Red Plus or Red Pro drive.

Just any drive should do, in particular external USB drives which you won't even bother to shuck for this application

Nice, I will look around and see what my options are.

This won't provide resiliency against a drive failure.

I know, I was about sectors issues; since the drive will be rarely used I will monitor its condition regularly, hopefully catching any issue before it escalates to data loss.

Any ZFS parameter is compatible with ZFS replication. Copies=2 just means you'll wait twice as long to complete since everything will be written twice. And you'll need a 10 TB drive or larger to backup 5 TB.

Which means I can replicate a dataset with copies=1 into one with copies=2? Great!

If feasible, for these "once a month" backups, you can purchase 2 external powered drives (e.g, WD Elements 8TB+) and create a mirror vdev for the backup pool. Plus them in together, disconnect them together.

The first (full) replication might take a while, but it shouldn't be an issue after that.

I could do it, but I was thinking more on the line of a single drive; time is not of concern.

SMR might not even be "plague" in this application because the issue with ZFS is when resilvering, especially raidz# arrays, but you won't resilver an external backup on a single-drive pool. SMR, tough, sucks at long continuous writes, and that's precisely what you'll be doing when backing up.

I would prefer to avoid SMR in relation to ZFS.

Thank you both, will update in a while.

 

[Davvo]

It seems there are no CMR drives at the 6TB category; do I really need to go 8TB in order not to get SMR? It sucks!

 

[winnielinnie]

It seems there are no CMR drives at the 6TB category

There were as recently as 2020. The only certainty for CMR are capacities at 8TB+.

This is especially of interest for purchasing external drives, since you do not have access to the model number of the 3.5" drive within. (You cannot check ahead of time "Is this 6TB drive inside the USB enclosure for sure not SMR?") With 8TB+, you are certain to get a CMR drive, without needing to know the model number of the internal drive within the enclosure.

 

[Davvo]

In the end I settled for a 5TB SMR drive from Seagate (STKM5000400, which should contain a Barracuda): I spent a bit less, I don't care about speeds (I will plug it and let it run the backup), and it gives me the chance to personally experience wheter or not it will give me trouble.

I was wondering about encrypting the dataset on this one, but I am concerned about compatibility (my system pool is not encrypted).

 

[kiriak]

I do snaphot replication to an ext USB HDD in Core.
The ext HDD is encrypted because I keep it offsite.
The source datasets are unencrypted all except from one encrypted.
Some info on this is here

Making backup to a local external drive Encrypted- is it possible in CORE?

I have a TrueNAS CORE 13.0-U5.3 system. I also have two external USB drives on-hand from a previous setup, that I would like to use as backup drives. One stays local, and a replication task runs on a daily basis, the other is attached / imported as needed, the replication task is run, then the...

www.truenas.com

 

[Davvo]

I do snaphot replication to an ext USB HDD in Core.
The ext HDD is encrypted because I keep it offsite.
The source datasets are unencrypted all except from one encrypted.
Some info on this is here

Making backup to a local external drive Encrypted- is it possible in CORE?

I have a TrueNAS CORE 13.0-U5.3 system. I also have two external USB drives on-hand from a previous setup, that I would like to use as backup drives. One stays local, and a replication task runs on a daily basis, the other is attached / imported as needed, the replication task is run, then the...

www.truenas.com

From the looks of it the source dataset is encrypted?

 

[Saoshen]

you might consider something similar to @ https://www.amazon.com/Sabrent-External-Duplicator-Function-EC-HD2B/dp/B0759567JT/

I have this device, and while I have not yet used it for a truenas external backup destination, I have been considering testing it out, by putting older/extra drives (as mirror pairs) in the dock, creating a backup pool, running a replication, then exporting and storing the bare drives offsite in a safe.

With sufficient spare (and properly labeled and protected) drives, you can do daily/weekly/monthly/etc rotations. If your backup set will fit into SSD's, I would recommend those, as this particular dock is quite fast with usb c + ssd's.

I have not checked or tested how well truenas can create and manage such an external backup rotation.

This kind of solution would of course some with some obvious benefits and drawbacks vs regular external drives, but that would be for you/your situation to test and determine.

 

[winnielinnie]

you might consider something similar to @ https://www.amazon.com/Sabrent-External-Duplicator-Function-EC-HD2B/dp/B0759567JT/

You risk bumping into the issue of colliding serial numbers if you use a USB caddy ("toaster"). Can cause problems with ZFS vdevs.

You're safer off plugging in two separate external USB drives into two separate USB ports.

 

[kiriak]

From the looks of it the source dataset is encrypted?

on the source (NAS) the dataset "kiriakos" is encrypted and the other datasets are unencrypted.

on the backup HDD the whole disk (pool) is encrypted. When I import it I have at first to unlock the pool and then to unlock the "kiriakos" dataset