1

Currently we have a "homemade" ESXi server that has been put in a Supermicro SC842i-500B chassis; this is obviously suboptimal, given that we do have a RAID 10 setup (6 SATA disks, with a MegaRAID SAS 9240-8i RAID controller) but the chassis does not support hot-swappable disks.

Finally, we got a more suitable case (Supermicro SC825TQ-R740LPB), which takes less space, should have a better air flow and, most importantly, has hot-swappable disk support.

Currently the disks are connected directly to the RAID controller through two SFF-8087 → 4xSATA cables; the new case introduces an extra layer - the backplane.

Given that I have no experience with SAS, server-grade hardware and backplanes, I have some doubts:

  • other backplanes I read about seem to connect to the RAID card directly through a single cable; here however the backplane has just 8 separate SAS ports and the controller has only 2 SFF-8087 ports; is it correct to use the split-cables we are already using, although they are supposedly SFF-8087 to SATA1?
  • what does having a backplane between the controller and the disks imply? Do I need to reconfigure something in the controller, or it should work "as if nothing happened" (given that I connect the same disks to the bays corresponding to the old connectors)?
  • the backplane has two I2C connectors and two sideband connectors, while the RAID controller doesn't seem to have anything like that, so I suppose that the controller and the backplane cannot communicate sideband data; should I be worried?

Edit ok, from what I gathered the sideband connector should come out from the SFF-8087 split cable, I'll check if the one we are currently using already has it and I didn't notice or if we have to buy another one; the other questions stand, however.


  1. Although, searching "SFF-8087 to 4 x SAS" yields only "SFF-8087 to 4 x SATA" results.
1

Don't worry! You have SFF-8087 to SATA cable and you can use it with the new backplane. RAID controller won't needed reconfiguration.

  • After one year, we finally did the move (yes, it took a while :-) ); in the end, we used SFF-8087 to SATA/SAS+sideband to connect to the backplane. Everything worked smoothly, the controller didn't require any reconfiguration and automatically detected the backplane, adjusting the "slot numbers" in storcli to match the numbers on the backplane. The backplane, in turn, does its thing and blinks correctly the LEDs corresponding to the various disks. Really neat! – Matteo Italia Aug 23 '17 at 15:17
  • The only gotcha I've ever run into migrating drive between LSI controllers is one system where the target controller was an older firmware version than the source. As long as you shut down the source system before drive removal, you can import the arrays to the target controller though Foreign Config by putting them into the hot swap chassis on the new system. Make sure your existing drives mount by UUID and not the older /dev/sdx nomenclature. If you want them to be in a particular LD position, simply install and import each array one at a time. the CLI will let you import them with LDAFTER. – Rowan Hawkins Apr 10 '18 at 21:58

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.