Dual-Path SAS Disks

[SlothCroissant]

Hey all,

I've got a few MD1200 DAS shelves that are connected to their host server via 2x SAS cables to 2x LSI HBAs. The MD1200 features two SAS controllers, and two connection mode options:

• "Unified" mode - where each controller has full access to all the disks - if a controller or cable or HBA goes out, the other controller/cable/HBA still has full control over the disks.
• "Split" mode - Each controller controls half the disks - if a controller or cable or HBA goes out, its disks go offline.

"Unified" mode is preferred due to lower risk of disks offline, but requires multipathd or similar to ensure that the host OS sees one disk with two paths, rather than two disks with one path. I'm noticing that Starwind CVM shows the latter - two disks are presented for each physical disk, same serial number with different HBA/Port/LUN IDs. So my 12 disks look like 24 in CVM.

In Proxmox or Linux in general, one would use multipathd to solve this - what is the equivalent in the Starwind CVM? Is this supported?

[yaroslav (staff)]

Hi,
Welcome to StarWind Forum.
In StarWind CVM, you can create MDRAID from those disks in any combination you like, until they the same.
Proxmox supports multipath, yet, it more implies to the 2 mirrors that are available over different paths so that the mirrored volume is seen by the system as one volume.