ESXi iSCSI datastore 1

[withanh]

I have two ESXi hosts that I want to share an iSCSI datastore. I have the first host connected to the datastore. I was able to format it with VMFS and have a VM successfully running on this disk space.

When I connect the second host, it tells me "Warning: The current disk layout will be destroyed. All file systems and data will be lost permanently."

How can I get the second host (and any subsequent ones) to use the same iSCSI datastore without losing any existing data?

Thanks!

h

 

[withanh]

Was digging around VMware's knowledge base and found this at

http://kb.vmware.com/selfservice/mi...guage=en_US&cmd=displayKC&externalId=6482648:

The LUNs presented to a set of servers must be presented with the same set of LUN numbers to all hosts.

For the above sample configurations, do the following:
Symmetrix: Present the LUNs to all FAs to use the same LUN numbers.
Clariion: Use a single Storage Group and add to it All ESX Servers that will access the LUNs assigned to that Storage Group. This will always present the same HLU (Host Logical Unit) number to all hosts in the same Storage Group.
Other Arrays: Use an equivalent process to maintain the same LUN numbers presented to all hosts that will share it.
If this is not possible, a solution to this issue is found on page 109 of the SAN Configuration Guide at

http://www.vmware.com/pdf/vi3_esx_san_cfg.pdf.

This solution is presented below for your convenience, with updates from August 9, 2006 that correct some issues in the original text.
Issues with Offline VMFS Volumes on Certain Arrays

On some arrays, it may not be possible to display the LUN with the same LUN ID across hosts. As a result, the ESX Server system incorrectly detects the LUN as a snapshot and places it offline. Examples of storage arrays for which the same LUN ID may not be visible for a given LUN across hosts are Clariion AX100 and few IBM TotalStorage Enterprise Storage Systems (previously Shark Storage systems).

Note: If you use Clariion AX100 with Navisphere Express, you cannot configure the same LUN ID across storage groups. You must instead use a version of Navisphere software that has more comprehensive management capabilities. For IBM TotalStorage 8000, you need to recreate these LUNS.

To resolve issues with invisible LUNs on certain arrays:

In the VI Client, select the host in the inventory panel.
Click the Configuration tab and click Advanced Settings.
Select LVM in the left panel and set LVM.DisallowSnapshotLUN to 0 in the right panel.
Warning: When LVM.DisallowSnapshotLUN is set to 0, no snapshot LUNs should be presented to the ESX Server host. Otherwise, data corruption may result. For details, see "State 3 - EnableResignature=no, DisallowSnapshotLUN=no" on page 110 of the SAN Configuration Guide at

http://www.vmware.com/pdf/vi3_esx_san_cfg.pdf.

Rescan all VMFS volumes.
After the rescan, all VMFS volumes are available.

I did this and rescanned the storage adapters. After doing so, the LUN was presented in storage as an available volume.

Thoughts, ideas, comments, good, bad, indifferent...If this is a viable solution, then I'll stick with it and bring my blade server into production.

Thanks!

h