How Virtual Machines Access Data on a Fibre Channel SAN

[almasry]

Hi

I have EMC SAN storage and HBA Qlogic card  installed on a VSphere 5 server

how I can access the LUN that I created on the SAN on a virtual machine.

please help step by step as I'm a new on the VSphere

[spravtek]

I think this video will get you on your way: Storage Solutions with Mutlipathing FC Targets with VMware

[Schmoog]

So to do this you will need to use a raw device mapping.

Step 1- create lun, and present it to all hosts in your cluster using the same lun id

Step 2- rescan all hba's on all hosts in your cluster

Step 3- edit settings on your vm, add hard drive, choose raw device mappings, and you should be off to the races.

a note about compatibility mode- physical compatibility mode is required if you are using the lun for microsoft cluster services, or if you want to be able to grow the lun without shutting down the vm. however in physical mode, if you take a snap of the vm, your lun will not be included. Virtual compatibility mode doesn't work with cluster services, and requires brief downtime if you want to grow the lun, however it is included in snapshots and hence backup if you're using a vmware integration for your backup

[LOAGANATHAN]

Confirm that the ESX host is ready to use its host bus adapter (HBA). Select an ESX host, and then choose the tab "Configuration." Select "Storage Adaptors." Select the HBA device. Confirm that the "Type" field displays "Fibre Channel."

Fibre Channel SAN connections are typically configured using HBA devices. Before an HBA can be configured to connect to a SAN volume, it must be configured for use. If this is not the case, it is necessary to reinstall the HBA hardware device.

Read more: How to Add LUN to VMware ESX | eHow.com http://www.ehow.com/how_6907811_add-lun-vmware-esx.html#ixzz27CTF8xdA

[almasry]

Dear LOAGANATHAN and all,

thank you for your reply.

i already discovered the HBA on the "Storage Adapters" and attched the LUN on "Stoarge" (as the attached screen shoot)

but my Q is how to map LUN on a virtual machine.

when i tried to add "Raw Device Mappings" from the Virtual machine >>Edit Settings >>add Hard drive  i found the RDM is disabled "grayed"

[Schmoog]

so the trick with rdm is that there can't be any existing vmfs on it. so while you do want to rescan, it can't be mounted in storage. remove the vmfs partition, and delete it from storage, then go to add hard disk on the vm again and rdm will be no longer grayed out. obviously im assuming there is no data on this lun. this operation will destroy any information contained in this lun since we're reformmatting it.

[almasry]

Dear Schmoog and all,

thank you very much the RDM is availabe now.

what i did      ESXI >>configuration>>Storage and unmount the LUN

after mins from VM >> add Hard Disk >>>the RDM is availabe.

thank you again for your support and help.

i have one more Q .....is the performance on the LUN that attached on the VM as the same as the performance on LUN that attached the physical server through the HBA directly ?

[Schmoog]

The performance of the rdm will be the same as the performance of your esxi host.

Because it's using the same hba as esxi and the other vms, i wont go so far to say that its equal to a physical box though since it's a shared environment.

That being said, i have 50 vms with rdms on 3 hosts in one of my environments and I've never had a performance problem at all.

Connected by DROID on Verizon Wireless

[Schmoog]

For what it's worth, if you're new to fc, it is a highly efficient, very high performing storage medium.

Connected by DROID on Verizon Wireless