[Help] Snapshot consolidation possible? Hourly>Daily>Monthly

[tnaspain]

Just started with TerraMaster and using Latest TOS7.x

Ran into an immediate Snapshot problems. On both the filesystem snapshots and shared folder snapshots.
Doing hourly snapshots, the system only allows 1024 snapshots. That is a very short period of time. 44 days.
It should be at least 10,000 snapshots, to be more useful. 30,000 snapshots would be even better, as that would be 3 years.
As they do not take up much space, why such a restrictive current limitation?

My 15 year old NetGear NAS automatically consolidated hourly snapshots> daily > monthly.
So before recently switching to TerraMaster NAS, I had many years of snapshots available to go back to.
If TerraMaster had this feature, a grand total of 1024 snapshots would be more than enough.

TOS 7.x does not seem to have that function, or I can not find it. Does it exist?

If not, I would ask the TerraMaster staff to add this as a new feature for the next update version of TOS7.

What do you say? Thanks.

WORKAROUND?
I created a shared folder called Daily Snapshots on Volume 1, and then a subfolder in there for each shared folder that I want a daily snapshot for. Named after shared folders receiving the snapshots, e.g. Folder-1-Daily, Folder-2-Daily, etc.

Thinking that would allow both hourly snapshots in the regular shared folders (which I am now doing) and then a daily snapshot stored in another location, so both could be made.
But trying to set up the daily snapshot and saving it to a different folder, other than the folder it is taking a snapshot in, is NOT possible.
Can't find a way to point storage of various daily snapshots to a different specific storage folder on the volume.
And then I wanted to do the same for montly snapshots.

I see that you can NOT store more than one type of snapshot (eg. hourly and also daily) in the same shared folder.
They system does not allow this.

Setting up the snapshots, I can not point the storage to those subfolders.
This also tells me that the TOS 7 system limitation is that a snapshot can only be stored in root shared folder. AND NOT OF A SUBFOLDER in that root shared folder.

Can someone please tell me the exact steps to setting up a daily and setting up another monthly snapshot for a particular shared folder that already has hourly snapshot folder in it?
(Each snapshot has to be in a separate subfolder, system does not allow 2 snapshot types in one shared folder).

Can this be done? If not, I would suggest that TerraMaster add this as a second new feature for the next update of TOS7 also.

[EriChan]

Thank you for the detailed testing and for sharing your feedback regarding the snapshot functionality in TOS 7. We would like to clarify the questions regarding the snapshot limit, tiered retention policy, and the proposed workaround.

1. Why is there a limit of 1024 snapshots?

TOS 7 file system snapshots are based on Btrfs Subvolume and its Copy-on-Write (CoW) mechanism. When a snapshot is created, unchanged data blocks are initially shared between the snapshot and the original Subvolume, so creating a snapshot does not require a full copy of the original data.

As the number of snapshots increases, Btrfs needs to maintain more Subvolumes, extent references, and related metadata. A large number of snapshots can also increase the overhead associated with snapshot deletion, space reclamation, and certain file system maintenance operations. When features such as qgroups are enabled, additional metadata and space accounting operations may introduce further overhead.

For this reason, TOS sets a limit of 1024 snapshots for a single shared folder as a product-level safeguard. This limit is intended to control the metadata and maintenance overhead that can accumulate when a very large number of snapshots are retained over a long period.

2. Does TOS 7 support Hourly → Daily → Monthly GFS retention?

Currently, TOS 7 does not support a multi-tier GFS (Grandfather-Father-Son) snapshot retention policy.

We understand that the requested workflow is more specific than simply maintaining separate hourly, daily, and monthly schedules. For example, the expected behavior could be:

• Create one snapshot every hour and retain the latest 24 hourly snapshots.
• After the hourly retention period has passed, retain one representative snapshot as the daily snapshot and remove the other hourly snapshots.
• Continue retaining daily snapshots for a longer period.
• At a later stage, retain representative daily snapshots as monthly snapshots for long-term historical recovery.

In other words, the requirement is for snapshots to move between different retention tiers over time, allowing high-frequency snapshots to be gradually replaced by lower-frequency long-term snapshots.

TOS 7 currently does not provide this type of automatic snapshot promotion or tiered retention mechanism. A snapshot task uses a single retention policy, and the same shared folder cannot currently be assigned multiple independent snapshot schedules for different retention tiers.

3. Why can the snapshots not simply be stored in another folder?

A Btrfs snapshot is itself a Subvolume and uses CoW to share data blocks with the original Subvolume. It therefore works differently from copying snapshot data into an ordinary directory as independent files.

At the Btrfs level, Subvolumes and snapshots can exist at different locations within the same Btrfs file system, and Btrfs also provides mechanisms such as send/receive for transferring Subvolumes between file systems.

However, TOS 7 currently does not provide an option to specify another shared folder or custom location as the management destination for snapshots. In addition, a single shared folder cannot currently be associated with multiple independent snapshot schedules.

Therefore, creating additional folders to implement separate hourly, daily, and monthly snapshot tasks cannot achieve the requested tiered retention behavior through the current TOS 7 snapshot implementation.

4. Feature request

We understand that the main requirements are:

• Support for multi-tier snapshot retention, such as Hourly → Daily → Monthly.
• Automatic retention of selected snapshots when moving from a high-frequency tier to a longer-term tier.
• More flexible retention rules for the same shared folder.
• The ability to maintain short-term high-frequency recovery points while keeping selected long-term historical versions.

We have recorded these requirements and will forward them to our product team for consideration in future TOS development.

Thank you again for the detailed testing and for sharing your use case and suggestions with us.

[tnaspain]

Thank you so much, EriChan, for the detailed confirmation of what I tried, and why my attempts did not work.

Hopefully something can be done to enable a longer snapshot retention time in the next TOS7 update