I currently have a zfs pool with mirrored vdevs, and it’s working well. It only has HDDs. I was planning to add an SSD I have lying around as a Metadata Special Device, since I’ve read that it can improve performance by quite a bit. I’ve also read that if I do that, and if the special device dies, I lose my pool.
Now, I don’t want to buy new SSD pairs for mirroring this one, so is there a way to ensure that the metadata is also stored on the HDD as usual, along with the SSD? I guess I want it to work like a cache for the metadata, and not the only place for it.
Thanks for the reply. That is my understanding. That it’s basically expanding the pool, and hence has same redundancy/backup requirements. I was wondering if it’s possible to set up a metadata cache. From the replies, it seems like that’s not possible for ZFS.
I’ve never heard of such a thing, and not even sure how that would work.