Questions About Navigating Storage Upgrade Options

[I3lackR0se]

Hey all! Running through a new storage expansion on my system, and I've run into a few unknowns I can't find the answers to in the documentation or searching past threads. My build is in the signature, but the tldr is that I'm running on the X10SL7-F on 11.2-U8, and I'm tapped out on direct HDD connections to my board (x6 4TB WD Red's and x6 8TB WD Red's). I currently have x6 additional 8 TB WD White's ready to shuck and install. In an ideal world, I'd like to extend my 2x(6 drive Z2 vdev) pool to a 3x(6 drive Z2 vdev, but I can't figure out if this is a good idea under Freenas's best practices. And where possible, for everything I do to be as reliable, cheap, and low effort (in that order, where it matters). Specifically:

1. The recommended hardware document states that the X10SL7-F can only have 14 drives "directly connected". Alternatively, I've seen threads about people using SAS Expanders with the mobo's LSI 2308 to get additional drive connections on this board on Freenas. But isn't the LSI 2308 a RAID controller, which is a major no-no for Freenas? Were these cases individuals ignoring what they should be doing, were they fine because they weren't using ZFS specifically but still ran Freenas, or is this setup fine and I've just misunderstood something?
2. If adding additional drives via a SAS Expander is viable, am I taking a significant risk by adding a 3rd vdev to my pool? If so, how many 6 drives vdevs would be "too much"? Documentation recommended 3-9 disk width per vdev, but I can't find much on what the recommended depth of vdevs per pool is, or how that factors in with the individual vdev pool width. Seemingly having a large number of medium-to-high width vdevs is bad even if they are the recommended size, since any one vdev going down tanks the pool and each additional one is compounding your chances of failure. I'm just unclear on determining what's typically considered "high risk". If it is a bad idea, I could of course create a brand new pool, but this creates additional maintenance burdens in needing to point different applications to different or multiple pools and managing their individual capacities.
3. If utilizing a SAS Expander and adding an additional 6-drive vdev is otherwise reasonably safe, I'm a little fuzzy on what hardware and logistics work best for this. I've looked into it, but it's very new waters for me. Is this a reasonable approach (financially and logistically)?: Flash the LSI 2308 to IT mode with the 20.00.07.00 driver, put in a RES2SV240, remove my all my current SATA HDDs from the SATA and the SAS LSI ports, adding 1 Mini SAS to SATA reverse breakout cable to 4 of those SAS LSI ports and then plugging the other end into any port on the RES2SV240, then run 5 Mini SAS to SATA breakout cables to the remaining ports on the RES2SV240, and finally running those breakout cables back to all the HDDs old and new, and then start up everything should be working (minus needing to add the 6 new drives to their own vdev in the pool)?
4. My current extra drive enclosures are basically a couple metal frames screwed together with some fans slapped on. I was considering trying to do a simple upgrade to that as part of this process to something more robust, such as these 5-bay hot swap enclosures. If I'm reading everything right, I can fit 2 of these in my R4 Define, and then take 2 more and put them in a cheap second case setup adjacent to the R4. Is that the simplest way to go about managing all these external drives without needing to buy and install a whole new (and potentially very expensive) server chassis?

Thanks for anyone who took the time to read that massive wall of text! And sorry if I missed something obvious when I was looking for answers myself in the documentation / forum history. Hope everyone is having a good day!

 

[danb35]

But isn't the LSI 2308 a RAID controller, which is a major no-no for Freenas?

No, it's a SAS HBA, and quite compatible.

 

[I3lackR0se]

No, it's a SAS HBA, and quite compatible.

Oh interesting. I hadn't stumbled on this term before. So I guess it's an HBA that has RAID-controller like features I just need to make sure to not use. Cool, thank you!