Use an SSD as a Hot Spare?

[RodMor74]

Hello,

I have a recently purchased NAS, with configurations as shown below:

TerraMaster NAS F4-424 Pro (TOS 5.1.145)
1 x M.2 NVMe SSD 1TB WD Red SN700 NAS (CACHE)
4 x Seagate Constellation ES ST2000NM0011 SAS 2TB 3,5" (BTRFS/TRAID)

The question is this:
Can I use the other SSD slot to put an SSD 2TiB disk in and use it as a hot spare?

Any help will be welcome.
Thank you very much.

[Gremlin]

Seems to me that you cannot mix HDD and SSD on same raid array and you would also be mixing SATA and Nvme hardware in the event that the hot spare were required. I also suspect you cannot 'hot spare' the ssd cache. You could reconfigure your second ssd and the original ssd as a raid pair for the cache (to provide resilience) but that would be 'wasting' storage as a lot of the ssd would not be available. Depending on your usage ssd (Hyper)cache may not even be needed - something to look into.

[RodMor74]

Thanks for the insights!
So, in a first analysis, that's why I put only the 4 HDDs in RAID... the only SSD I have now, I'm using it for Hyper Cache... is there any inconvenience in this configuration? I saw some videos about this, and a lot of people use SSD for Cache...

As for the free slot for another SSD, I thought I could use it for hot spare, as it would be extra security, but I don't know if it's possible... thanks.

[Gremlin]

You have 1TB ssd set aside for cache. You have 4x2TB raid, so max of about 5.75TB storage (presuming all used for storage pool and one volume using all of that pool - cache is allocated per Volume). Then consider actually how much ssd space is being used for that cache. Ratio of total space on ssd to actual cache size? That would be my "inconvenience factor"

{Things may change when a "proper" installation version of TOS6 appears and we can choose to install a (raid) os on 2 x nvme with fast nvme storage for apps alone. However, at the current rate of progress, there will be (better) hardware options available by the time that happens.}

[TMzethar]

Although rare, it is possible to use M.2 NVMe SSDs as a hot spare for RAID.
In addition, ATA disks are not supported, so please use SATA disks.

[RodMor74]

Hello!
Thank you very much for the recommendations.
Regarding the type of disk, I guess I put the word "SAS" by mistake... According to the reference of the disks, they are SATA, right?
Thanks.

[Gremlin]

Yes SATA

as per Seagate:

The use of SATA hard drives on SAS controllers is made possible by the fact that both share the same infrastructure and have similar features. SATA drives may be plugged into SAS controllers. SAS drives cannot be plugged into SATA controllers.

[RodMor74]

I have already corrected the text of my signature, with the correct information.
Thanks for your help