I have a LSI 9300-16i connected to an Adaptec AEC-82885T 36-Port SAS-3 12Gbps Expander internally via a SFF-8643 to SFF-8643 cable, and the Netapp connected to the the Adaptec card externally via single SFF-8644 to SFF-8644 cable.
All is well and the netapp shows up in Unraid.
Now for the interesting things.
Directly connected to the Netapp, none of the Seagate EXOS X16 16TB disks will spin up.
I tried Kapton tape on the 3.3v pin on the disks and still nothing.
I have a bunch of SAS to SATA interposers, with 2 different model numbers.
The different models when attached to the SATA disks and plugged in to the Netapp allow the Seagate disks to Spin Up and be detected.
The interposers ending in part number 02D do not pass temp data.
The interposers ending in 04B do send the temp data.
I have 9 disks now connected to the 04B interposers, and ran a preclear on them with pre and post check. All was well and pretty fast considering disk size.
The new disks have been added to my array and are working, but fix common problems tells me that write cache is disabled on the drives connected via interposers.
I stopped the array, and as a test put on of the drives without an interposer in to a USB enclosure and looking at its disk log, write caching is enabled.
It seems that the SAS to SATA interposer is killing the ability to use write caching, but removing the interposers prevents disk from spinning up at all. I tried the standard commands to try and enable the write caching when the drives are connected to the interposers, but that fails.
Any thoughts? Should I just live with this and be happy or am I taking a significant performance hit here?
Thanks!