Disk cache size

I have a 4 disk raid 5 using OMV 7 in clean state. Three of the SATA drives are WD40EFPX (256Mb cache) and one is a WD40EFZX (128Mb cache). All 4 drives are CMR. The drive controller is an LSI 9207-8i in IT mode. My drive bay has a multicolor LED for each drive, green for power and orange for drive activity.

I notice that the three WD40EFPX drives stay green all the time and only the WD40EFZX drive shows any drive activity indicated by the orange LED flickering occasionally when the raid is being written to. Of course all the drives are being written too but I wonder why I only see the LED change color for the one drive. I tried swapping drive bays and the activity light behavior follows the drive.

Does the fact that one drive has a lower cache size than the other three possibly cause this?

Zitat von vcruser

Does the fact that one drive has a lower cache size than the other three possibly cause this?

The WD40EFZX drive has 10 MB/Sec slower interface transfer rate according to the data sheet. Possibly due to the smaller cache size

Today I replaced this drive so now all the drives in the array are identical and the drive access LEDs are behaving as expected now.