Romex Software Forum

Hello,

I’m using an intel rst raid 0 (2 ssd) as a cache drive.

Since there is no ntfs file system on those or, it’s primocache’s proprietary filesystem, is TRIM suported and enabled?

How would I check that?

TRIM isn't currently supported for L2 cache volumes, last I knew. But if you over-provision the drives before creating the L2 (5% minimum, 10-15% ideal), the controller and the drive can do garbage collection more efficiently. TRIM isn't absolutely necessary when GC is working efficiently, though it does help.

I believe Romex is working to add TRIM functionality to a future version of Primocache.

How would I go about over-provisioning? I'm using Samsung SSDs. That is, without removing the L2 cache drive and breaking up the array to over provisioning each SSD (860EVO 250GB).

The drives are part of RST raid 0 array and not accessible via Samsung Magician.

Normally you'd use Samsung Magician on stand-alone drives to over-provision them (basically leave x% of free space at the end of the drive). Magician can't see the drives behind a hard RAID 0 (controller-based) array, so it can't do it for you.

You could emulate the function however, by re-sizing the L2 cache volume size to say 90% or 85% of the effective RAID volume size. When the drive sees free space at the end, it's own internal controller should automatically use it for GC.

If the drives are 100% provisioned for the L2 storage you will have inefficient Garbage Collection performance (in addition to no TRIM currently in Primo). Personally I'd just blow away the L2, re-do the array as soft RAID 0 (through Windows Drive Management), and only use 85% of the available space as a new L2. That may also allow Samsung Magician to see the drives in case you want to do any other management/maintenance on them. I stopped using Intel RST many years ago when it became more problematic than helpful. The CPU hit to soft-RAID functions now is so small as to be unnoticeable.