Resizing volume to use all space - why the warning?

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giskard
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Resizing volume to use all space - why the warning?

Post by giskard »

My QNAP NAS has 4 x 4 TB disks provisioned as a thick volume that supports snapshots. I've noticed that not all of the disk is being used, with a few TB free so I've decided to just resize the volume. In the Resize volume wizard I clicked the button labelled Set to Max and got the warning shown as below:
Capture2.JPG
I've checked through the documentation but it makes no mention that I can find as to why "Manually reserving additional space is recommended" rather then just using the max available using the button. Can anyone please educate me :)
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P3R
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Re: Resizing volume to use all space - why the warning?

Post by P3R »

If you expand the volume to use all available capacity there will be no room left for the snapshots. Snapshots are stored outside of the volume.
RAID have never ever been a replacement for backups. Without backups on a different system (preferably placed at another site), you will eventually lose data!

A non-RAID configuration (including RAID 0, which isn't really RAID) with a backup on a separate media protects your data far better than any RAID-volume without backup.

All data storage consists of both the primary storage and the backups. It's your money and your data, spend the storage budget wisely or pay with your data!
giskard
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Re: Resizing volume to use all space - why the warning?

Post by giskard »

I thought that snapshots were stored inside the volume, unless Pool Guaranteed Snapshot Space is configured, which it isn't.
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Re: Resizing volume to use all space - why the warning?

Post by P3R »

giskard wrote: Mon Jun 22, 2020 8:18 pm I thought that snapshots were stored inside the volume...
They aren't. Snapshots are always stored directly in the pool (outside of the volume), guaranteed snapshots space only determine if some of the space should be protected against automatic deletion if something else claim the space.

Quoted from the online help (with my underlining added):
What is guaranteed snapshots space?
When using snapshots to preserve changes to data, the snapshots will be stored directly in the storage pool. Snapshots are automatically removed when the system needs to free up storage pool space for other purposes, such as thin provisioning.

Enabling guaranteed snapshot space ensures that a certain number of snapshots will be retained, by reserving a specified amount of the storage pool for snapshots.
RAID have never ever been a replacement for backups. Without backups on a different system (preferably placed at another site), you will eventually lose data!

A non-RAID configuration (including RAID 0, which isn't really RAID) with a backup on a separate media protects your data far better than any RAID-volume without backup.

All data storage consists of both the primary storage and the backups. It's your money and your data, spend the storage budget wisely or pay with your data!
giskard
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Re: Resizing volume to use all space - why the warning?

Post by giskard »

Ah okay, thanks for the clarification :)

So according to the storage pool management, I have a capacity of 10.89 TB, of which 10.37 TB is allocated, leaving 528.51 GB unallocated, so that's available for snapshots. The volume size is 9.97 TB (91.60% of the pool) so that leaves 8.4% space for snapshots, of which 408 GB has been used and there's 529 GB unallocated which I guess is available for snapshots, so I've allocated a bit less than 10% for snapshot storage, whereas 10% is recommended.

I reckon I'll be okay with 8.4% space available for snapshots and anyway, I've plenty of free space in the volume in case I do need to shrink it to allow for more snapshot space.
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RobAinscough
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Re: Resizing volume to use all space - why the warning?

Post by RobAinscough »

Just to be clear.

I have a Thick Volume, but I'm NOT using snapshots, so I assume I can just ignore this message or is there some other "gotcha" down the road I might run into?

Cheers, Rob.
For me, it is far better to grasp the Universe as it really is than to persist in delusion, however satisfying and reassuring. - Carl Sagan
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Re: Resizing volume to use all space - why the warning?

Post by dolbyman »

correct
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Re: Resizing volume to use all space - why the warning?

Post by P3R »

RobAinscough wrote: Tue Jul 27, 2021 2:08 am I have a Thick Volume, but I'm NOT using snapshots, so I assume I can just ignore this message or is there some other "gotcha" down the road I might run into?
The gotcha is that it's very hard to predict the future. In the future you could realize that you want to use snapshots after all, or that you need an iSCSI LUN for something or that you for some reason want a separate volume for some usage. Therefore I think it's always a bad idea allocate all space to a thick volume unless you actually need it within some months.

My recommendation is to only expand a thick volume to what you think you'll need in the next 6-12 months.
RAID have never ever been a replacement for backups. Without backups on a different system (preferably placed at another site), you will eventually lose data!

A non-RAID configuration (including RAID 0, which isn't really RAID) with a backup on a separate media protects your data far better than any RAID-volume without backup.

All data storage consists of both the primary storage and the backups. It's your money and your data, spend the storage budget wisely or pay with your data!
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RobAinscough
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Re: Resizing volume to use all space - why the warning?

Post by RobAinscough »

P3R wrote: Tue Jul 27, 2021 3:42 amMy recommendation is to only expand a thick volume to what you think you'll need in the next 6-12 months.
Sounds like a solid suggestion, but can't I just reduce the volume size (assuming I haven't used it all) if I need to have snapshots or iSCSI LUN at a later date?

Cheers, Rob.
For me, it is far better to grasp the Universe as it really is than to persist in delusion, however satisfying and reassuring. - Carl Sagan
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Re: Resizing volume to use all space - why the warning?

Post by P3R »

RobAinscough wrote: Tue Jul 27, 2021 5:21 am Sounds like a solid suggestion, but can't I just reduce the volume size (assuming I haven't used it all) if I need to have snapshots or iSCSI LUN at a later date?
Yes you can unless some data for some reason have been stored towards the end of the volume. Then it couldn't be shrunk all the way back any more.

I can't think of any good arguments for why it would be wise to do a maximum expansion long before the storage is needed but I can think of situations where it could limit you in the future.
RAID have never ever been a replacement for backups. Without backups on a different system (preferably placed at another site), you will eventually lose data!

A non-RAID configuration (including RAID 0, which isn't really RAID) with a backup on a separate media protects your data far better than any RAID-volume without backup.

All data storage consists of both the primary storage and the backups. It's your money and your data, spend the storage budget wisely or pay with your data!
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RobAinscough
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Re: Resizing volume to use all space - why the warning?

Post by RobAinscough »

I guess it depends on your requirements, in my case I payed for the space, I'm going to use the space and not reserve it for some feature that I will not use. I would view that as a waste of money with no practical application since I don't have a requirement for snapshots nor LUN.

With video editing I can fill up 38 TB (RAID 5) NAS very quickly (4K/8K video at 10 or even 12 bpc).

Within a few months it's very likely I'll be looking for another QNAP or swapping out my 10TB for 18TB drives (if the TS-932X can handle those sizes).

Cheers, Rob.
For me, it is far better to grasp the Universe as it really is than to persist in delusion, however satisfying and reassuring. - Carl Sagan
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Re: Resizing volume to use all space - why the warning?

Post by P3R »

RobAinscough wrote: Tue Jul 27, 2021 7:21 am ...since I don't have a requirement for snapshots nor LUN.
If you want maximum capacity and know that you will never want to use any of the storage pool features in the future a static volume would probably be a better choice. A thick volume at maximum pool capacity is slower and static volumes are typically recommended for maximum performance applications like video editing.
RAID have never ever been a replacement for backups. Without backups on a different system (preferably placed at another site), you will eventually lose data!

A non-RAID configuration (including RAID 0, which isn't really RAID) with a backup on a separate media protects your data far better than any RAID-volume without backup.

All data storage consists of both the primary storage and the backups. It's your money and your data, spend the storage budget wisely or pay with your data!
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RobAinscough
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Re: Resizing volume to use all space - why the warning?

Post by RobAinscough »

I like Qtier which is not available in Static.

But to be clear, I don't work directly with video files stored on the NAS that would be too slow regards of network speed or Volume configuration. The Flow for video editing project:

1. Camera output stored to 2-4 TB M.2 (high speed NVMe).
2. Editing work is done exclusively with these large video files on the M.2's ... usually Adobe Pr, Ae, Au, Me ... depends on codec and conversion and/or proxies.
3. Once editing is final, exports to required formats.
4. Original camera output files are moved from 2-4 TB M.2 over to NAS for archive (pulled back down if needed again)
5. Exports will also be moved to NAS for archive post delivery to client

The biggest exposure is a failing motherboard in the NAS (Power supplies, RAM, fans, etc. can be replaced with QNAP spare parts shop). But according to QNAP I can simply remove the 9 drives and put them in another empty QNAP system that's not even the same model so long as it supports Storage Pools. So definitely want to stick with Storage Pools.

These QNAP setups are pretty amazingly resilient ... light years ahead of the old Western Digital NAS I used to work with (Yikes those were horrible, my data would be more reliable on 5.25 floppy disks).

Cheers, Rob.
For me, it is far better to grasp the Universe as it really is than to persist in delusion, however satisfying and reassuring. - Carl Sagan
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