SSD + HDD Configuration question

[dedrick427]

I have four 2tb SSDs (Samsung 870 QVO) and four 6TB HDDs (Seagate Iron Wolf Pro 7200rpm, with 4 open bays that I can later expand with). The OS is installed on an M.2 on the motherboard. When installing I noticed I have a lot of option to use the SSDs to speed up the HDD pools, like cache, file tables, and so on (I can't remember off the top of my head), but it seems like it'd have to use the entire SSD for these

I planned on grabbing a RAID controller to be able to create virtual drives, then present a few smaller volumes and one large volume so that I could use the SSDs to speed up the HDDs and also for faster storage, but now I'm reading to avoid RAID controllers (and I agree, but I'm kind of limited here)

I'd like to maximize my performance and storage -- this will be used for a few VMs, a Plex Server, NextCloud, and possibly a repo for Steam games. Is there a way to software-RAID the SSDs, and then use those volumes for the cache/file info/etc? Is there something obvious I'm over-looking? I've spent so much money so far and I really don't want to back myself into a bad configuration

More detailed parts list:

Ryzen 5600G APU
4x Samsung 2tb 870 QVO
4x Seagate 6TB Iron Wolf Pro ST6000NE000
SilverStone DS380B Case (4 2.5 bays, 8 3.5 bays)

I also have on had:
LSI 9240-8i (I can flash it either way)
SupaHub 8-port SATAIII card

I'm not opposed to buying a new HBA/SATA controller if I need to

Thanks!

 

[jgreco]

You probably want to stop and get up to speed on TrueNAS and ZFS first. It is unlike anything you're likely to have worked with in the past.

First off, RAID controllers are an absolute no-no with ZFS. It isn't a "agree with but kinda limited here" thing. It's nonoptional. See

What's all the noise about HBAs, and why can't I use a RAID controller?

1) An HBA is a Host Bus Adapter. This is a controller that allows SAS and SATA devices to be attached to, and communicate directly with, a server. RAID controllers typically aggregate several disks into a Virtual Disk abstraction of some sort...

www.truenas.com

L2ARC, which you're referring to as "cache", isn't recommended until you have a minimum of 64GB of RAM in the host system, and then, it's preferable to start off with maybe 5x system RAM and go no more than 10x system RAM. So a 512GB SSD is probably the largest practical option for cache.

The QVO's are reported to be generally problematic due to low endurance.

 

[NugentS]

"The QVO's are reported to be generally problematic due to low endurance."
4-5 weeks in a RAID5 array (not ZFS) acting as a iSCSI store for relatively non busy VM's and they died, badly.

 

[dedrick427]

Okay, if I switch out the QVOs with other SSDs, what else would I need to look into, configuration wise? Just make two pools, one SSD and one HDD and forget about using the SSDs for anything other than storage?

 

[Jessep]

Okay, if I switch out the QVOs with other SSDs, what else would I need to look into, configuration wise? Just make two pools, one SSD and one HDD and forget about using the SSDs for anything other than storage?

Yes