datapool setup with 4xHHD and a SSD

[juscox]

Overview
Platform: FREENAS-MINI-2.0
Version: TrueNAS-SCALE-23.10.0.1
4 × 5.46 TiB (HDD)
14.91 GiB× 1 (SSD)
447.13 GiB× 1 (SSD)

Would the proper (loose interpretation of proper) setup of the above be a raidz2 using the 4 HHDs? should the single SSD 447.13.GiB be setup as a log,spare,cache,metadata if that is even possible? can those options be splitup onto one SSD?
i am a bit confused as to what the ssd are best used in conjunction with the hhd. very much a newbie i have had this setup for a while but have been unable to spend time poking around at it to setup for a home network.
these are the drives that originally came with the device

currently
raidz2 4 × 5.46 TiB (HDD)
unused 14.91 GiB× 1 (SSD)
unused 447.13 GiB× 1 (SSD)

 

[Arwen]

Yes, using the 4 x HDD as a RAID-Z2 is appropriate.

Using the 447.13 GiB SSD as a SLOG, (aka Log), Spare, L2ARC, (aka Cache) or Metadata is not appropriate:

• Their are specific use cases for a SLOG, synchronous writes, like with NFS or iSCSI, you don't appear to have the need. Plus, the SSD device would need special characteristics to work well as a SLOG.
• You can not spare a large disk, with a smaller disk.
• Unless you have maxed out your RAM, a L2ARC is not really indicated. (But, could be added later, live.)
• ZFS Special vDevs, (aka Metadata), using 1 SSD are HIGHLY NOT recommended. Any Special / Metadata vDev should have the same redundancy as the the data pool. For example, minimum of 2 way Mirror and with a RAID-Z2 data pool, even a 3 way Mirror is appropriate. Loss of a Special / Metadata vDev means the loss of the entire pool, including the data vDevs...

Sometimes you can buy a hardware bundle for a FreeNAS / TrueNAS server that includes a SLOG device and L2ARC device. That would match the sizes, (16GB for SLOG and 512GB for L2ARC). But, that does not mean they are appropriate for your use case.

You can use the larger SSD for an application pool, understanding that it has no redundancy. (A backup to the RAID-Z2 could be done daily to compensate for the lack of redundancy.) However, the RAID-Z2 pool should be fine for lightweight applications or even just a few heavy hitting applications.