ESX 4, MD3000 - Virtual Disk Not On Preferred Path

[214kris]

Hello All,

I have two clusterred ESX 4 working on Dell R805 each and it works with Dell MD3000 Matrix.

Each ESX has two iscsi controllers, one is with "red" ip range and one with "blue" ip range, then MD3000 has two units of iscsi controllers, and each unit has two controllers also with the same ip range configuration as ESX servers.

All is connected as documentation of MD3000 says, here is a picture:

And now, problem appear on MD3000, it is shows Virtual Disk Not On Preferred Path warning.

ESX - 1 and ESX - 2 has access to storage where i have two virtual discs, everything working OK, without any errors from ESXs so i build all virtual environment and started to use it, after that noticed that: Virtual Disk Not On Preferred Path warning from matrix 😕

After little search i found on one of my ESX under: configuration>storage adapters that there are no paths:

altouhg both discs on matrix are connected to this ESX and working fine.

Next ESX under the same tab has paths:

I check all connection, all ethernet cards working fine, and i can connect to MD3000 by Unit1 and Unit2 from different initiator (from XP workstation for instance) so i think there is something with VMware.

Is there any idea what should I do with?

[Jahei]

Hi,

its known problem with MD3000. There should be new firmware for MD3000, it fixes the problem.

You need to shutdown all IO-operations and connections to MD3000 when you upgrade firmware.(really great to drive all down! if you don't have another storage system available)

If you don't have service window to upgrade the firmware of MD3000, you can connect MD3000 with the management and change the preferred paths from the configuration.

As far as i have understood is that ESX hosts and MD3000 wants to use different "preferred" paths and that is causing this error message.

[PaulusG]

Hello 214Kris,

You can find documnetation about configuring an MD3000i in an ESX 4.x envronment on:

The Dell Modular Disk Storage Manager Client is also usefull detecting problems:

1. Choose you storage array in the upper left corner

2. Go to Tab iSCSI

3. Check the "View/End iSCSI Sessions" and "View iSCSI Statisctics"

Paul Grevink

Twitter: @PaulGrevink

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[214kris]

Hi All,

Thank You for Your suggestion, they are seems to be right.

I found on my MD3000i (it is 3000i not 3000 as I wrote, sorry) that preffered owner on one of my Virtual Discs is not corresponding wit current owner and i think this cause the warning on MD3000i - here is a piece from log:

Virtual Disk name: 1

Virtual Disk status: Optimal

Preferred owner: RAID Controller Module in slot 0

Current owner: RAID Controller Module in slot 0

Virtual Disk name: 2

Virtual Disk status: Optimal

Preferred owner: RAID Controller Module in slot 1

Current owner: RAID Controller Module in slot 0

I can change the owner of Virtual Disk 2 by Modular Disk Storage Manager Client under:Change Virtual Disk Ownership/Preferred Path but i worry to do it on working system, there are images of vm's and i dont know what can happen 😐

[PaulusG]

There is little risk, changing the preferred path.

To be sure, I usally perform this action not during critical business hours. Until now never had problems with a VM after performing this action.

I do administration on several MD3000i SANs, and for some reason it sometimes happens that a LUN is no longer on it's preferred path. In most cases a network disruption or powerouttage was the cause.

As the other contributor said, it is a good idea to have the latest firmware installed on the MD3000i SANs.

In the storage manager, you can also configure email alerting, this keeps me well informed about the status of the SANs.

Paul Grevink

Twitter: @PaulGrevink

If you find this information useful, please award points for "correct" or "helpful".