DanC111
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Contributor

Adding SAN Storage to Cluster

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Hey, Im new to VMWare, so I apologize if this seems like a silly question to some.

I've got ESX 4.1 hosts in a cluster, and the hosts are connected to my SAN. I can add storage via each host, and create a datastore, but it shows as a local datastore, which I assume means I get no HA for VMs on that LUN.

How can I add storage to the cluster, so that it's available to all hosts?

Thank you.

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weinstein5
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The way Anton has described it is the way it works - if the LUN on your SAN is presented to each host it will show up - I have never created a cluster with just a single host so I can not speak to what how it will display in the vSphere client - the way I would check it is look at the configuration tab for your host and check the storage adapters and if the LUN is hsowing up under the FC HBA than it is on the SAN -

Since there is no data on the LUN I would go ahead and expose it to another host - the host does not have to be part of the cluster to do this - and see if the description changes.

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piaroa
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What kind of SAN connection have your hosts? FC, iSCSI ? Are your LUNs shared and properly configured?

With local storage you won't be able to use HA, VMotion ,etc.

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DanC111
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We're using FC. The LUN path is currently only connected to one physical server. I didn't want to add the others just yet. If I add the others, will vSphere automatically add the storage to the cluster?

I've tested in a cluster where there was only one server, and the storage shows as local there too (the difference being that with one server, all servers in the cluster were attached ot the storage).

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AntonVZhbankov
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>How can I add storage to the cluster, so that it's available to all hosts?

Present LUN from SAN to each host with the SAME LUN ID. After that you create datastore on one host and it will be automatically connected to all hosts.


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MCITP: SA+VA, VCP 3/4, VMware vExpert

http://blog.vadmin.ru

EMCCAe, MCITP: SA+VA, VCP 3/4/5, VMware vExpert http://blog.vadmin.ru
piaroa
Expert
Expert

Correct, you need to allow all your hosts access to your LUNs. Also, when you create a new datastore (one per LUN), all other hosts with visibility will mount after a reboot or storage rescan.

Also, LUNs should be smaller than 2TB in size.

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AntonVZhbankov
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>If I add the others, will vSphere automatically add the storage to the cluster?

Yes.

and the storage shows as local there too

How does it appear that storage is local?


---

MCITP: SA+VA, VCP 3/4, VMware vExpert

http://blog.vadmin.ru

EMCCAe, MCITP: SA+VA, VCP 3/4/5, VMware vExpert http://blog.vadmin.ru
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DanC111
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Well that would just be too easy if that were the case!

I didn't want to proceed attaching the storage to other hosts without confirming that there weren't more steps.

So in my test environment, where there is only one host in the cluster, it's showing as local storage simply because there is only one host that can see the LUN?

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DanC111
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Well that would just be too easy if that were the case!

I didn't want to proceed attaching the storage to other hosts without confirming that there weren't more steps.

So in my test environment, where there is only one host in the cluster, it's showing as local storage simply because there is only one host that can see the LUN?

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piaroa
Expert
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It should not be showing as local if you have a datastore residing in an FC SAN.

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DanC111
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Currently, I have one test cluster with a single host. I have presented a LUN to the host, and created a datastore.

I went to perform a task, Deoploying an OVF Template, and when I do, it shows that the datastore's Access is set to "Single Host."

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weinstein5
Immortal
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The way Anton has described it is the way it works - if the LUN on your SAN is presented to each host it will show up - I have never created a cluster with just a single host so I can not speak to what how it will display in the vSphere client - the way I would check it is look at the configuration tab for your host and check the storage adapters and if the LUN is hsowing up under the FC HBA than it is on the SAN -

Since there is no data on the LUN I would go ahead and expose it to another host - the host does not have to be part of the cluster to do this - and see if the description changes.

If you find this or any other answer useful please consider awarding points by marking the answer correct or helpful

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View solution in original post

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DanC111
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Ok, but if that's the case, what keeps multiple servers from accessing the same LUN at the same time, and causing file locking issues if this isn't handled at the cluster level?

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mcowger
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Immortal

Thats the job of the VMFS filesystem. It mediates all access to the LUNs to prevent issues with concurrent access. it uses SCSI-2 locks for sensitive operations.

--Matt

VCP, VCDX #52, Unix Geek, Storage Nerd

9773_9773.gif

--Matt VCDX #52 blog.cowger.us
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weinstein5
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It is handled by the VMFS file system - a file lock is maintained in the metadata section of the volume so if a another ESX hosts goes to write to the same VMDK it is stopped -

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DanC111
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Ok, thank you for all of the help, this definitely clears things up for me!

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bas000m
Contributor
Contributor

Hi ,

I am new to VMware, Kindly please help to do this .

I need to expose same LUN to My VMs , two VMs shares same LUN .

I need to use RDM for this LUN .

Thanks in advance .

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