New to LSI HBAs/backplanes? Make sure any consumer grade SSDs support DRAT and RZAT

I’m just making this as an announcement that hopefully someone else will benefit from. If you’re using LSI HBAs (9300, 9305, 9211 etc) make sure your combination of hardware and software allow the trim (DRAT and RZAT) to performed or you’ll get this really weird fluctuating write speed. One of my SSDs (WD Blue) supported it, and the other (Crucial MX500) did not, so it was tanking performance. The SSDs can’t take out the trash without these features

I know this is probably common knowledge for experts/career individuals here, but for me it was confusing as hell for several hours due to some other recent hardware/setup changes, leading me to think it was the HBA or software issue

You can use hdparm -I /dev/sdX | grep TRIM to find out if a drive supports them.


root@Tower:/var/log# hdparm -I /dev/sdc1 | grep TRIM
           *    Data Set Management TRIM supported (limit 4 blocks)
           *    Deterministic read ZEROs after TRIM

DRAT = Data Set Management TRIM
RZAT = Deterministic Read Zero after TRIM

The Unraid forums have a thread on the topic that includes some discussion about LSI HBA firmware revisions.

There used to be a list of drives somewhere, too.