EDIT: This is my expander card (I thought DL380 was the card but that is the compatible server) – **761879-001 HP 12G DL380 G9 SAS Expander Card**
I’m building an Unraid box as an onsite backup of our NAS. I’ve been moving about 40TB of data to it in increments. At one point I added 4 16TB EXOS (pre-cleared and added to the array). when I started the next file transfer things started getting weird.
Before the new drives were added my cabling setup was Port1 of 9260 going into the expander and then 2 8087 cables going to my backplane, 4 drives per 8087.
When I went to add the other 4 drives I needed to plug in a third 8087 to another row on the backplane and I also added a second cable from Port2 on 9260 to another port on the HP expander (I thought I had read that this was an OK scenario – that the expander would autoroute everything and this second input would give it more bandwidth – I can’t find much in the docs on this)
Pre-clearing went fine but as soon as I started adding data to these drives the whole array started acting weird. Drives started switching back and forth from available to unassigned and if I started the array it would start saying single drives had 100k+ read errors. I would stop the array and then it would say array back to normal no errors. All my drive have good SMART status with no errors. This was happening to random drives usually one would randomly be doing this after a boot, then on next boot it would be a different drive.
Since the pre-clear went ok I hadn’t really thought about the cable mod I had done so I started trying to troubleshoot other things. Anyway, it dawned on me that I had added that second input cable so I removed it and now everything is back to normal (so far)
1. Does the HP DL380 only want one input to expand? was it freaking out cause it doesn’t want two connections to the HBA
2. Could be backplane splitter or cable issue but it wasn’t any one drive or Bay.
3. Maybe that second input cable is bad – but if I only need 1 input I’m not gonna mess with it.
So in the future when this gets more drives I thought maybe I will keep adding 8087 cables to the expander with only one input from HBA then use the other HBA output for the last 6th backplane input.