The mirrored volumes should automatically trim and optimize in Windows, but if you notice issues, it might be a problem with your setup.
Optimization or Defragmentation must remain off by default for SSDs. This safeguards the device. SSDs don’t require defragmentation. You can enable it, but there’s a chance of harming your data and drive.
Not true as of Windows 10, which knows what a SSD is. The optimiser runs a forced TRIM operation on empty parts of SSDs which can pick up missed areas for whatever reason. This is normal, routine and desired (not not essential) operation. If you fail to do this, at worst you lose some write performance and maybe lose endurance a bit faster. As for not being able to run it, I do recall that depending on how RAID is set up, it might not be possible to pass through the TRIM command. I thought that was largely got around now, but I could be wrong.
To the best of my understanding, BIOS-based RAID configurations generally don't support TRIM. However, most modern operating systems offer full software RAID solutions such as Btrfs, ZFS, or Windows Storage Spaces that do accommodate TRIM functionality within a RAID setup.
This brings us back to the main issue in the discussion—why Windows can't handle it under these conditions. The only idea I have is that mirrors or parity-based systems might struggle here, as TRIM could leave parts of the data in an unclear state. For a mirror, this shouldn’t be an issue, but many design choices seem unclear to me, which makes me wonder if this was another case. Deterministic TRIM was introduced to address this, though I have no idea how it works or who supports it.
I honestly don’t understand much about Storage Spaces. Since I’m not using it, I’m unclear on its restrictions. I think it should work just like any other RAID software, but I’m not sure if anything unusual is preventing it. It’s possible the developer has special drivers or software that interfere, or maybe the RAID was set up differently than expected.
Because the controller acts like a virtual drive and lacks TRIM support, it seems outdated for newer systems. Some may enable it if it's recently updated.