I found in my setup that mixing disk controllers in the same tRaid was very unstable. I had all kinds of problems with a setup that was using a dell perc card and the intel mobo onboard controller. (8 drives on perc and 4 on intel) I ended up getting an intel SAS expander so that I could put all 12 drives on my dell perc card and have had zero problems in 3 years since. I also found that WD black drives to be very unstable. They seem to start out fast but over time get really really slow, which I think contributes to timing problems. I have been running a mix of Hitachi and Seagate 7200 Rpm drives with no issues. The SAS expander was expensive but worth it.
interesting. thanks.
yes, I'm using 3 controllers essentially. The motherboard SATA controllers, and two M1015 cards...one on a x16 slot, and one on a x8 slot.
Thanks for confirming the WD black thing. I'm going to replace them with HGST and see if that helps, the ones I already use don't give me problems (except for the ones on the mobo sata).
I have two pools:
the first pool uses the x16 M1015 along with the mobo sata. I tried an HP SAS expander, but I noticed the speeds got affected drastically (especially with the verify operations). SO I wanted to retain the speeds by not using an expander, but that means i can only have 8 drives per M1015.
the second pool is on the slower x8 M1015 card, no expander. That one continually gave me the problems I've posted here, but I have it going to an external box with additional external cables, and the only drives really giving me problems on that pool is the WD black. SO hopefully, that fixes that problem, and the pools work fine after that.
So I'm learning the pros and cons here. WD Black is bad for flexraid apparently, even though they are supposed to be good drives. The HGST drives seem ok. mixing the controllers is bad, at least mixing the mobo with the M1015.
What are people's experiences with SAS expanders on traid and speed? I forgot the numbers but it made the verify operations extremely long, like it went from maybe half a day or one day to weeks even.