Virtual Disk Not On Preferred Path

Hello billmatthews,

Yes you can redistribute the Virtual Disks while the MD is in production  see below:

The alert on the system is due to a virtual disk not being on the preferred path. When virtual disks are created, they are assigned to one of the two controllers as a preferred communication path. If that path is not available – due to a network issue, controller reset, etc. – the array will communicate via the alternate controller. In some cases the communication does not shift back to the primary path when it becomes available again.  To correct this you just need to manually redistribute the virtual disks back to their preferred paths.

To redistribute virtual disks:

1.            Open Modular Disk Storage Manager (MDSM)

2.            Click on the Support tab

3.            Select Manage Raid Controller Modules

4.            Click on Redistribute Virtual Disks

•             You will get an alert telling you that this will disrupt communications if you do not have the multipath drivers installed. You can ignore this message and proceed. If you still have access to the virtual disk that is not on preferred path, you have multipath drivers installed

Please let us know if you have any other questions.

We are facing same problem, it's daily and has now become an annoyance, is there a permanent fix to this issue ? 

Hello IAmP,

I would upgrade the firmware on the MD & see if the issue is still happening. Here is a link to the latest firmware for the MD3200. http://www.dell.com/support/drivers/us/en/19/DriverDetails/Product/powervault-md3200?driverId=TVVCK&osCode=WS8R2&fileId=3330571982&languageCode=en&categoryId=SG

Also when you do the firmware upgrade you will have to upgrade MDSM. Here is a link to the resource CD so that you can update that as well. http://www.dell.com/support/drivers/us/en/19/DriverDetails/Product/powervault-md3200?driverId=JPKXM&osCode=WS8R2&fileId=3335653817&languageCode=en&categoryId=CD

Here are also the steps to perform the upgrade just in case you don’t have them.

Steps to update the firmware:

1.         Ensure you have a tested backup of the data contained on the array

2.         It is highly recommended to gather support bundle from the "Support" tab of the MD Storage Manager before performing any firmware upgrade operations. Also recommend getting another support bundle after the upgrade is complete.

3.         You must stop all I/O going to the array

4.         Load MDSM to verify connectivity, then close MDSM but leave the main management screen open

5.         From the main management screen in MDSM use the “upgrade raid controller firmware” on the “devices” screen to upgrade to the latest firmware

6.         Verify connectivity through MDSM

7.         Update the hard drive firmware if applicable

8.         Reboot the stack

a.         Power down the server(s)

b.         Power down the MD3000(i)

c.         Power down any attached storage (MD1000/12xx)

d.         Leave the power off for 2-3 minutes

e.         Power up in reverse order

9.         Verify connection to the array and virtual disks and verify that data is presented to each of the connected servers

Please let us know if you have any other questions.

Yep, for me the fix was firmware 7.84.47.60.  Very stable now. 

Hello IAmP,

Which model of MD do you have? Also what is the current version of firmware that is running on the MD? I have seen some cases of this where your virtual disk keeps switching between controllers and if you upgrade the controllers firmware it resolves the issue.

Please let us know if you have any other questions.

MD 3200 is the model and looks like just a step down of a  Firmware as Bill. I know last time we had to do firmware upgrade it turned out Second Raid card on it was bad (that is for a brand new system it came with bad card).

Yeah that was a version we had a problem with too.  I think my version or later should fix it for you. 

Looks like will be spending the weekend in the office doing the upgrade !

I am having the same issue to where I am getting the preferred path is not available. We have not had connectivity to this RAID Controller Module for months now. We still have access to the VMs so there must be multi-path support for our VMware? In this case should I not "redistribute virtual disks" during the day in production?

If not, do I need to shut down all affected VMs to stop I/O? 

EVENT:

Virtual Disk not on preferred path due to AVT/RDAC failover

THANK YOU!!!!

Hi,

what is the impact of Redistributing the virtual disks ? any restart downtime ?

Please help, thanks.

sajid