Cache SSDs Recognized?

[jhlee2222]

Hi All,

I'm a new user and just set up my TrueNAS Mini-X, with five standard hard drives and two SSDs in the smaller bays, intended to provide a speedy cache where needed.

After booting up, I see the blue lights on all drives. However, I'm checking in the interface of the device and I only see five drives in the pool. Should my SSD drives show up in the pool as well, or is there another location in the interface I'd see them? My SSDs required an adapter. Some searches seem to imply the adapters may or may not be compatible with TrueNAS.

I realize this is a very newbie question, but I can't find a direct answer. To be clear, I'm not trying to troubleshoot a particular problem at this point, I'm trying to determine if I HAVE a problem first.

Thank you in advance.

 

[Patrick M. Hausen]

You would have to add the disks to the pool as an e.g. L2ARC vdev. But first you need to consider if that makes sense at all. How much memory do you have in this thing? If you have 32 G or less, adding what you think is a read cache would possible worsen your performance, not improve it.

Similarly an SLOG is not a write cache, and unless you have very specific applications won't do anything at all. Definitely not for general file sharing via SMB.

Maybe a special metadata vdev is something that would put those two SSDs to good use.

For any help with the decision we would need to know your hardware configuration, size and type of all the drives, memory, ... as well as the specific applications you intend to run.

Kind regards,
Patrick

P.S. You might want to start with familiarising yourself with the basic concepts of ZFS: https://www.truenas.com/docs/references/zfsprimer/