topic Re: Redundancy on DS2405 in Disk Enclosures

Redundancy on DS2405

Dave Chamberlin — Tue, 17 Mar 2009 20:22:21 GMT

Greetings
I have a DS2405 disk system with dual controllers connected to an rp7420 server (hpux 11.23). It currently has 2 disks, using mirrorux to mirror the 1st disk to the 2nd. I have 2 available fiber ports on this server, and I would like to have a redundant HW path if possible. How do do this (using PVlinks is assume)? thanks

Re: Redundancy on DS2405

Torsten. — Wed, 18 Mar 2009 03:35:01 GMT

Hi Dave,

let's assume you connect only 1 cable first.
You will see 2 disks. Create your VG and LVOLs. Now connect the second cable. You will see "another" 2 disk devices. Now simply vgextend these devices to your existing VG and you will have your alternate pathes in vgdisplay (this is PVLINKS).

Re: Redundancy on DS2405

TTr — Wed, 18 Mar 2009 10:46:22 GMT

You may want to use the first HBA as the primary path with the first disk and the second HBA as the primary path with the second disks. This way both HBAs do i/o. When you set up your logical volumes and mirroring, use only the the primary paths of each disk when you run the lvcreate/lvextend command for mirroring

Re: Redundancy on DS2405

Dave Chamberlin — Wed, 01 Apr 2009 21:43:25 GMT

I am confused. I initially connected tow cables, one to port0 on the 1st controller and port 1 on the second controller. When there were two cables, I only saw one set of paths, but had daily EMS events complaining about duplicate paths.
When I removed the 2nd cable, I now see two sets of paths, but there is only one cable - to port 0 on the first controller. I am attaching ioscan showing these paths. There are actually 4 disks, though only 2 are in use.

Re: Redundancy on DS2405

Torsten. — Thu, 02 Apr 2009 02:53:32 GMT

You need to connect to port 0 on each controller. Make sure the rotary switch setting is the same on both controllers.

Re: Redundancy on DS2405

TTr — Thu, 02 Apr 2009 10:55:40 GMT

You must use port 0 on each side of the 2405 to connect your fiber cables, port 1 is for cascading to additional 2405s.
Check that the port 0 module on the side that shows NO_HW has good connectivity and link lights on both the server side and the 2405 side. Both sides of the 2405 should have identical status lights. Check your cables and SFPs in case any of them are bad. You can pull the SFPs from port 1 and use them in port 0 if one of them is bad. I do have a 2405 and port 1 does not even have SFPs installed and both controllers are set to 0 on the rotary switch. The two controllers are separate fabrics so the address being the same is not an issue.