Re: [pve-devel] TrueNAS over iSCSI: Snapshot Management

Re: [pve-devel] TrueNAS over iSCSI: Snapshot Management

[Lorne Guse via pve-devel]

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From: Lorne Guse <boomshankerx@hotmail.com>
To: Proxmox VE development discussion <pve-devel@lists.proxmox.com>, "m.carrara@proxmox.com" <m.carrara@proxmox.com>, Morgan Littlewood <morgan@truenas.com>
Subject: Re: TrueNAS over iSCSI: Snapshot Management
Date: Sun, 5 Oct 2025 04:11:49 +0000
Message-ID: <DM6PR17MB346659F576D1D081C71CCC6DD0E2A@DM6PR17MB3466.namprd17.prod.outlook.com>

I was wondering if anyone got a chance to see this message. I'd like to know if there is a mechanism for importing TrueNAS snapshots into Proxmox.

This would allow things like periodic snapshots on the TrueNAS side to integrate into Proxmox.

--
Lorne Guse
________________________________
From: Lorne Guse <boomshankerx@hotmail.com>
Sent: Saturday, September 27, 2025 10:45 AM
To: Proxmox VE development discussion <pve-devel@lists.proxmox.com>; m.carrara@proxmox.com <m.carrara@proxmox.com>; Morgan Littlewood <morgan@truenas.com>
Subject: TrueNAS over iSCSI: Snapshot Management

I'd like to get some input on snapshot management relating to TrueNAS. Currently, Proxmox does not allow for multigeneration rollback of snapshots.

TASK ERROR: can't rollback, 'preupgrade' is not most recent snapshot on 'nas:vm-803-disk-0'

I was wondering if there is a way for Proxmox to allow for the use of TrueNAS periodic snapshots without breaking Proxmox snapshots.

Is there a way to import TrueNAS snapshots into Proxmox via the API?

Could multi-generation rollback work because TrueNAS supports it?


--
Lorne Guse

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Re: [pve-devel] TrueNAS over iSCSI: Snapshot Management

[Morgan Littlewood via pve-devel]

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From: Morgan Littlewood <morgan@truenas.com>
To: Lorne Guse <boomshankerx@hotmail.com>
Cc: Proxmox VE development discussion <pve-devel@lists.proxmox.com>,  "m.carrara@proxmox.com" <m.carrara@proxmox.com>
Subject: Re: TrueNAS over iSCSI: Snapshot Management
Date: Sun, 5 Oct 2025 15:02:37 -0700
Message-ID: <CABr3vq+8FF-T0NC=aTXq6ke_PgSYjJhbo0Pk4BPT64vRHbMC+w@mail.gmail.com>

I'd recommend that Proxmox do the snapshots (periodic or not)  so thta it
is aware of all snapshots and their retention time.   It is the master and
decides when snapshots should be deleted.

Proxmox also has a schance to quisece the VMs and so the snapshots will be
application and not just crash-consistent. This is a cleaner experience for
the VMs and users.

TrueNAS will just take, list and delete the snapshots efficiently based on
plugin and API request.





On Sat, Oct 4, 2025 at 9:11 PM Lorne Guse <boomshankerx@hotmail.com> wrote:

> I was wondering if anyone got a chance to see this message. I'd like to
> know if there is a mechanism for importing TrueNAS snapshots into Proxmox.
>
> This would allow things like periodic snapshots on the TrueNAS side to
> integrate into Proxmox.
>
> --
> Lorne Guse
> ------------------------------
> *From:* Lorne Guse <boomshankerx@hotmail.com>
> *Sent:* Saturday, September 27, 2025 10:45 AM
> *To:* Proxmox VE development discussion <pve-devel@lists.proxmox.com>;
> m.carrara@proxmox.com <m.carrara@proxmox.com>; Morgan Littlewood <
> morgan@truenas.com>
> *Subject:* TrueNAS over iSCSI: Snapshot Management
>
> I'd like to get some input on snapshot management relating to TrueNAS.
> Currently, Proxmox does not allow for multigeneration rollback of snapshots.
>
> TASK ERROR: can't rollback, 'preupgrade' is not most recent snapshot on
> 'nas:vm-803-disk-0'
>
> I was wondering if there is a way for Proxmox to allow for the use of
> TrueNAS periodic snapshots without breaking Proxmox snapshots.
>
> Is there a way to import TrueNAS snapshots into Proxmox via the API?
>
> Could multi-generation rollback work because TrueNAS supports it?
>
>
> --
> Lorne Guse
>

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Re: [pve-devel] TrueNAS over iSCSI: Snapshot Management

[Lorne Guse via pve-devel]

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From: Lorne Guse <boomshankerx@hotmail.com>
To: Morgan Littlewood <morgan@truenas.com>
Cc: Proxmox VE development discussion <pve-devel@lists.proxmox.com>, "m.carrara@proxmox.com" <m.carrara@proxmox.com>
Subject: Re: TrueNAS over iSCSI: Snapshot Management
Date: Mon, 6 Oct 2025 01:09:53 +0000
Message-ID: <DM6PR17MB3466C924D9FC9565703D5B64D0E3A@DM6PR17MB3466.namprd17.prod.outlook.com>

Ok, I won't overcomplicate it then.
________________________________
From: Morgan Littlewood <morgan@truenas.com>
Sent: Sunday, October 5, 2025 4:02 PM
To: Lorne Guse <boomshankerx@hotmail.com>
Cc: Proxmox VE development discussion <pve-devel@lists.proxmox.com>; m.carrara@proxmox.com <m.carrara@proxmox.com>
Subject: Re: TrueNAS over iSCSI: Snapshot Management


I'd recommend that Proxmox do the snapshots (periodic or not)  so thta it is aware of all snapshots and their retention time.   It is the master and decides when snapshots should be deleted.

Proxmox also has a schance to quisece the VMs and so the snapshots will be application and not just crash-consistent. This is a cleaner experience for the VMs and users.

TrueNAS will just take, list and delete the snapshots efficiently based on plugin and API request.





On Sat, Oct 4, 2025 at 9:11 PM Lorne Guse <boomshankerx@hotmail.com<mailto:boomshankerx@hotmail.com>> wrote:
I was wondering if anyone got a chance to see this message. I'd like to know if there is a mechanism for importing TrueNAS snapshots into Proxmox.

This would allow things like periodic snapshots on the TrueNAS side to integrate into Proxmox.

--
Lorne Guse
________________________________
From: Lorne Guse <boomshankerx@hotmail.com<mailto:boomshankerx@hotmail.com>>
Sent: Saturday, September 27, 2025 10:45 AM
To: Proxmox VE development discussion <pve-devel@lists.proxmox.com<mailto:pve-devel@lists.proxmox.com>>; m.carrara@proxmox.com<mailto:m.carrara@proxmox.com> <m.carrara@proxmox.com<mailto:m.carrara@proxmox.com>>; Morgan Littlewood <morgan@truenas.com<mailto:morgan@truenas.com>>
Subject: TrueNAS over iSCSI: Snapshot Management

I'd like to get some input on snapshot management relating to TrueNAS. Currently, Proxmox does not allow for multigeneration rollback of snapshots.

TASK ERROR: can't rollback, 'preupgrade' is not most recent snapshot on 'nas:vm-803-disk-0'

I was wondering if there is a way for Proxmox to allow for the use of TrueNAS periodic snapshots without breaking Proxmox snapshots.

Is there a way to import TrueNAS snapshots into Proxmox via the API?

Could multi-generation rollback work because TrueNAS supports it?


--
Lorne Guse

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Re: [pve-devel] TrueNAS over iSCSI: Snapshot Management

[Max R. Carrara]

On Mon Oct 6, 2025 at 3:09 AM CEST, Lorne Guse wrote:
> [...]

Hi Lorne, hi Morgan!

Sorry—only now finally got some time to look into this.

Regarding multi-generational snapshot rollbacks: That is something
that's possible actually; our `lvm-thin` storage supports that, for
example [0]. You're probably running into the default implementation [1],
hence the error.

We don't support it for our ZFS pool storage though [2] (and thus also
not for the ZFS over iSCSI storages), since `zfs rollback` doesn't
support it without destroying intermediate snapshots [3].

The user can still do rollbacks on older snapshots, they just have to
delete the intermediate ones first, in this case. (So basically what
`zfs rollback` requires one to do.)

With all that being said, I agree with Morgan here; it's best to just
let PVE manage the snapshots and whatever contents are on the volume, as
it is a cleaner experience for the user. (Principle of least surprise
and all that.)

Hope that helps! If you need anything else, feel free to ping me! (:

[0]: https://git.proxmox.com/?p=pve-storage.git;a=blob;f=src/PVE/Storage/LvmThinPlugin.pm;h=ccefd0eb24630a4ae5e206002760126dfce9304a;hb=refs/heads/master#l366
[1]: https://git.proxmox.com/?p=pve-storage.git;a=blob;f=src/PVE/Storage/Plugin.pm;h=2291d72d929b9de83f7703aae146372e4b663860;hb=refs/heads/master#l1325
[2]: https://git.proxmox.com/?p=pve-storage.git;a=blob;f=src/PVE/Storage/ZFSPoolPlugin.pm;h=3b3456b7482ad4388a757e80484412384a677da1;hb=refs/heads/master#l551
[3]: https://openzfs.github.io/openzfs-docs/man/master/8/zfs-rollback.8.html


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Re: [pve-devel] TrueNAS over iSCSI: Snapshot Management

[Morgan Littlewood via pve-devel]

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From: Morgan Littlewood <morgan@truenas.com>
To: "Max R. Carrara" <m.carrara@proxmox.com>
Cc: Lorne Guse <boomshankerx@hotmail.com>,  Proxmox VE development discussion <pve-devel@lists.proxmox.com>
Subject: Re: TrueNAS over iSCSI: Snapshot Management
Date: Mon, 6 Oct 2025 12:59:24 -0700
Message-ID: <CABr3vqKwJgwFu+A=Jjw_hSEwwjz=3X+ZU7kkBrmyuppWSaKxhQ@mail.gmail.com>

Rollback to last snapshot is acceptable for 99.9% of situations....

For deleting intermediate snapshots.. can this be done on TrueNAS UI or
does proxmox control this?
If done on TrueNAS, can Proxmox learn about (adjust to)  deleted snapshots?



On Mon, Oct 6, 2025 at 6:17 AM Max R. Carrara <m.carrara@proxmox.com> wrote:

> On Mon Oct 6, 2025 at 3:09 AM CEST, Lorne Guse wrote:
> > [...]
>
> Hi Lorne, hi Morgan!
>
> Sorry—only now finally got some time to look into this.
>
> Regarding multi-generational snapshot rollbacks: That is something
> that's possible actually; our `lvm-thin` storage supports that, for
> example [0]. You're probably running into the default implementation [1],
> hence the error.
>
> We don't support it for our ZFS pool storage though [2] (and thus also
> not for the ZFS over iSCSI storages), since `zfs rollback` doesn't
> support it without destroying intermediate snapshots [3].
>
> The user can still do rollbacks on older snapshots, they just have to
> delete the intermediate ones first, in this case. (So basically what
> `zfs rollback` requires one to do.)
>
> With all that being said, I agree with Morgan here; it's best to just
> let PVE manage the snapshots and whatever contents are on the volume, as
> it is a cleaner experience for the user. (Principle of least surprise
> and all that.)
>
> Hope that helps! If you need anything else, feel free to ping me! (:
>
> [0]:
> https://git.proxmox.com/?p=pve-storage.git;a=blob;f=src/PVE/Storage/LvmThinPlugin.pm;h=ccefd0eb24630a4ae5e206002760126dfce9304a;hb=refs/heads/master#l366
> [1]:
> https://git.proxmox.com/?p=pve-storage.git;a=blob;f=src/PVE/Storage/Plugin.pm;h=2291d72d929b9de83f7703aae146372e4b663860;hb=refs/heads/master#l1325
> [2]:
> https://git.proxmox.com/?p=pve-storage.git;a=blob;f=src/PVE/Storage/ZFSPoolPlugin.pm;h=3b3456b7482ad4388a757e80484412384a677da1;hb=refs/heads/master#l551
> [3]:
> https://openzfs.github.io/openzfs-docs/man/master/8/zfs-rollback.8.html
>
>

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[pve-devel] TrueNAS over iSCSI: Snapshot Management

[Lorne Guse via pve-devel]

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From: Lorne Guse <boomshankerx@hotmail.com>
To: Proxmox VE development discussion <pve-devel@lists.proxmox.com>, "m.carrara@proxmox.com" <m.carrara@proxmox.com>, Morgan Littlewood <morgan@truenas.com>
Subject: TrueNAS over iSCSI: Snapshot Management
Date: Sat, 27 Sep 2025 16:45:12 +0000
Message-ID: <DM6PR17MB34662F5ABDA587979C0FFDA2D019A@DM6PR17MB3466.namprd17.prod.outlook.com>

I'd like to get some input on snapshot management relating to TrueNAS. Currently, Proxmox does not allow for multigeneration rollback of snapshots.

TASK ERROR: can't rollback, 'preupgrade' is not most recent snapshot on 'nas:vm-803-disk-0'

I was wondering if there is a way for Proxmox to allow for the use of TrueNAS periodic snapshots without breaking Proxmox snapshots.

Is there a way to import TrueNAS snapshots into Proxmox via the API?

Could multi-generation rollback work because TrueNAS supports it?


--
Lorne Guse

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