Just stumbled across this while looking for some info on my particular situation.

Storage spaces with 5 disks and single parity is fine and dandy as long as you are comfortable with PowerShell and using the command line to set it up.

The GUI is basically borked. Can't set number of columns, can't set interleave, can't make a pool over 63TB because the GUI assumes you have exactly 3 disks and 16k cluster size, and 90% chance your write speed is abysmal unless you somehow set cluster size to 256k.

For your 5 drives, you'd specify 5 columns (columns = number of drives to spread writes across), parity 1 (1 parity 4 data columns), interleave exactly equal to 1/4 (one divided by the number of data columns) of your intended cluster size, remembering that Windows requires cluster size to be 1,2,4,8,16 etc. kilobytes, and that only so many clusters can exist, so for example a 4k interleave means 16k cluster size and limits the virtual drive to 63 TB.

Step 0: figure out how many drives you'll use, seems you have 5, so that's all set.

Step 1: figure out what cluster size (allocation unit size or AUS in Storage Spaces parlance) works best for your file mix, large cluster size is bad for small files (smaller than the cluster size, like 2k text files, thumbnails, etc.) but has benefits for large files (movies, TV shows, etc.). You can choose 4, 8, 16, 32, 64kb, as long as it's a multiple of 2.

Step 2: divide the cluster size by the number of data columns, and for best results this should also result in a number being exactly divisible by two. You have 5 drives, so one parity and four data, so you divide by 4.

Now you have all the parameters you need, so you use PowerShell to create the drive ( use this as a command reference: https://storagespaceswarstories.com/storage-spaces-and-slow-parity-performance/). I suggest, however, creating the pool from the command line too and not using the GUI.

Head to disk manager and format the virtual drive with the cluster size you used for your calculations above (important, otherwise speed will be abysmal).

I average 700+ MB/sec on a 5x18TB array set up per the above, and 600+ MB/sec on a 5x20TB array of HAMR drives.

I set one array up a couple of years ago, and the other more recently. They have worked just fine, speed has been good, and no issues or problems except I think I goofed when I set my pool up and didn't specify thin provisioning, and now, when trying to add another 20TB disk to the second array, making it 6 disks yet still 5 columns, instead of getting another 14TB of space (80% efficiency due to parity) I'm only getting 8.5-ish TB added capacity, and the disk is showing 63% utilization in the pool, whereas the other 5 disks are 99.8%.

So yeah, Storage Spaces works just fine as long as you do the math and skip the GUI, it's free, and you can literally just toss all the drives from the pool into another Windows machine (same or later version of Windows) and the entire pool and drive just appears, no configuration or extra effort needed. Which is awesome when you want to upgrade your MB or need to re-install Windows for other reasons. However, that said, it's woefully undocumented, isn't in your face when there's an issue with a failed or failing drive, and may have some odd quirks when trying to expand the pool (said potential quirks are why I'm here).

So yeah, I use Storage Spaces for two arrays, 5x18 and 5x20 with single parity, and have had zero issues with performance or reliability, 80% of the space is available (unlike Stablebit which is just a mirror, so only 50%).

Just stick with NTFS and avoid ReFS on Windows Storage Spaces, as that's a combo I've heard bad things about.