Best options for 2.5" (SFF) drives

[fun.hat]

Hello, I am an absolute newbie to NAS and Unraid specifically. At present I have a number of Raspberry Pis, an Intel NUC, and another small PC running Nextcloud, handling backups for my family's computers, a small Jellyfin instance, and hosting a game server. The backup is presently a single 4TB USB drive that is rapidly filling up, and other than the most critical information being duplicated in Backblaze, does not have any onsite duplication.

 

I recently got an old server that I want to use to replace all of this. I have looked at Rockstor and other options, but the ability of Unraid to add drives to an array over time draws me to it. My question is mostly about the hardware options for storage though. The downside of this server is that it is all 2.5" SFF bays. It has 2 200GB SSDs already, but the rest of the drives (6 of them) are 300GB HDDs. That's not nearly enough storage. I'm planning on using the existing SSDs as cache drives, and I am assuming that getting the biggest SSDs I can afford for the storage array would be the way to go? I know the parity drive has to be as big as the biggest drive, and right now 2-4TB SSDs seem to be generally affordable. It would seem logical that over time bigger SSDs will come about at a reasonable price point. If I have a 4TB parity drive and a couple of 4 TB drives in the array, is it easy to move the parity drive into the array and replace it with a bigger parity drive if, say, 8 TB drives become cheap in the future?

 

I'm also assuming that HDDs are not really a great option at this point in time. The biggest I've seen is 5TB, and it's not really cheaper than an SSD.

 

Thanks for any insight.

[trurl]

SSDs in the array cannot be trimmed.

 

You can create one or more pools outside the array (btrfs or ZFS) each with one or more drives. "cache" is the traditional pool, but you don't have to have a pool named cache, and you can use the pools for anything.

 

At least one data disk is required in the array, parity is not required. All drives in array and pools are part of user shares.

[trurl]

Some of these restrictions will be removed on future versions.

[fun.hat]

9 hours ago, trurl said:

SSDs in the array cannot be trimmed.

 

You can create one or more pools outside the array (btrfs or ZFS) each with one or more drives. "cache" is the traditional pool, but you don't have to have a pool named cache, and you can use the pools for anything.

 

At least one data disk is required in the array, parity is not required. All drives in array and pools are part of user shares.

Thanks. So I can hope that trimming in arrays comes in the future, but from what I have gathered SSDs tend to be unpredictable in where they store data and if they move it and collect garbage on their own. If I understand correctly, SSDs in the array work fine, but may gather junk over time because they can't be trimmed, and will degrade lifespan and performance. It sounds like for reliability the array should be all HDDs, assuming one intends to use a parity drive.