RAID5 upgrade - single disk or all

[bubbl07]

Hi all,

I currently have a TS-851 with the following configuration:
1x 250GB SSD for OS
7x 4TB HDDs in RAID5

If I were to replace a single 4TB HDD with one that's larger (say, 8 or 12 TB), would that actually increase the RAID5 capacity? This is probably a question not specific to QNAP and I wasn't able to find a clear answer so thanks for your patience.

Now, if this is theoretically possible for a RAID5, can anyone point me to any documentation on how to do it? I found https://www.qnap.com/en/how-to/knowledg ... ng-a-drive but that assumes you're replacing all the drives in the array.

Any help would be appreciated. TIA!

[OneCD]

Your new drive would only use 4TB of its capacity, and you'd need to add the new drive to the existing array. You can't add it as a "single" drive and include it in the array.

But - yes - your RAID5 would be increased by ~4TB.

[bubbl07]

Sorry, I meant to say replace one of the 4TBs with a larger drive. Updated to be more clear.

Thanks for the quick response, though - I assume the answer is "it will only use 4TB and therefore no impact to RAID capacity."

[OneCD]

... I assume the answer is "it will only use 4TB and therefore no impact to RAID capacity."

Yes, that's correct.

[bubbl07]

Separate question then: is there a way to decrease the size of a RAID5 while online?

What I'm envisioning is that I reduce the RAID5 to 6x4TB and add a 12TB HDD as a single drive. I imagine I could do this by recreating the RAID but would love to avoid having to wipe and then restore from backup.

[OneCD]

QTS doesn't support decreasing the size (or the removal of member drives) of a RAID5 array.

[pablobasito]

Separate question then: is there a way to decrease the size of a RAID5 while online?

What I'm envisioning is that I reduce the RAID5 to 6x4TB and add a 12TB HDD as a single drive. I imagine I could do this by recreating the RAID but would love to avoid having to wipe and then restore from backup.

Men, I was searching exactly for this possibility. I have a TS-453 Pro, with 4xHDD, all in a single RAID5; no spare disks.
I was hoping to remove one disk (so the data shouldn't be affected, 'cause the other 3 are still working and healthy), and then persuading the system to just use those 3 HDDs from now on.
In the meantime I could add a bigger 4th HDD, use it outside the RAID, do some moving, then when the first 3 HDDs are empty, totally remove the old RAID, and re-thinking at my strategy.
Actually, I really can't think to change all the 4 HDDs to improve my space. I'm sad, if this isn't contemplate as a possibility
I feel so dirty inside, if I have to use an external USB, adapters etc.

[dolbyman]

You should already have usb for backups anyways..so no reason to feel dirty (unclear why you would)