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mibu
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RDM - unable to extend disk

Hi all,

We have several file servers running. Disks are raw LUNs in virtual compatibility mode.

I have a problem trying to extend the disks as needed. I have presented a larger disk through in our EVA. I have rescanned all HBA's so I now see the correct new size in Virtual Infrastructure Client. I then shut down the server, and do a "vmkfstools -X 65G ". I get an error saying "Invalid parameter (1)".

i then made an error, and accidently ran the command with the machine powered on. This successfully extended the disk, but got a "file busy" on the vmdk file.

So I'm in a wee bit of trouble here Smiley Happy Anyone got an idea what to do? Alternatively, I got another disk (non-rdm) the same size as the one I'm trying to extend. Could I just edit the .vmdk manually with the variables for the new size? As the RDM is already physically larger, this should be all that's needed? .. or? Smiley Happy

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BUGCHK
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I would delete and then recreate the RDM pointer file while the VM is powered off.

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BUGCHK
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I would delete and then recreate the RDM pointer file while the VM is powered off.

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tgradig
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They only way we could extend a Raw disk was to attach it to a physical server, extend it, and then attach it back to the virtual server.

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mibu
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I was just suggested that elsewhere also. Kinda a "doh" moment. "Why didn't I think of that?". I must be too used to think of the disks as pure .vmdk files.

But thank you also, this is the proper solution to my problem. No need to make it more complex than it is Smiley Happy

Removing the mapping. And mapping it again did the trick for me.

Message was edited by:

mibu

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mibu
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Out of curiosity, was it attached to the VM in virtual compatibility mode or physical?

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mitchellm3
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We have two environments right now, 2.5.3 and VI3. Our file servers are on ESX 2.5.3. When we need to extend the RDM's, on our MSA 1500 we just expand the LUN. We then rescan the hbas so that the esx server sees the extra space. Once this is done, you just have to power off the VM file server. Leave it off for a good 30 seconds. When you turn it back on, you need to go into disk management and you'll see the extra space at the end of each volume. Then its just a matter of using diskpart to extend the volume.

We haven't tested this yet on our VI3 environment cause the Storage is a DS6800 which can't extend LUNs. Once we get in our SVC that will change. I'm guessing under VI3 you probably won't even have to turn off the VM to see the extra space. I only say this cause you can hot add hard drives which is pretty cool.

We only use vmkfstools to extend a .vmdk file and of course, the vm must be turned off to do this. That always works like a charm.

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mibu
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I've tried pretty much what you describe there. For me, after extending the LUN in our EVA, rescanning the HBA's and shutting down the VM, I was still not able to use diskpart to extend the volume.

As far as I've understood, this is because we run the LUN's in virtual compatibility mode. I'd like to be corrected if this is not the case, though. But my understanding is that this, as opposed to a physical mapping, means you usually have to use vmkfstools to extend the PDM-file. Have I completely misunderstood something here? In any case, this also did not work for me properly.

I've also understood, that using physical compatibility mode, I shouldn't even have to shut off the VM to extend the volume, as long as I have rescanned the HBA's.

However, if I need to shut down the VM. Disconnecting and reconnecting the raw mapping is not that big a deal at this point. It's just as fast as using vmkfstools Smiley Happy But it would be nice not having to shut down the VM in the first place.

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jeangaud
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It's been more than a year now since the last post.

Has anyone successfully extended a raw lun without rebooting the VM ?

Jean

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formulator
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We do this all the time but our RDMs are all in physical mode presented to windows guests.

All I do is extend the LUN on the array, go into disk management on the guest and refresh to make sure the free space is being seen at the end of the disk, stop IO to the LUN on the guest so if the LUN has a SQL DB on it stop SQL server. Then use diskpart to extend the volume and start SQL server again. I'm not sure if you really have to stop IO to the LUN but I always do to be safe, downtime ends up being a couple minutes with no reboot required.

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jeangaud
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Ok, it looks good.

I will try this test tonight in my test lab.

Jean

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jeangaud
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Do you use Round-Robin on raw LUN in physical compatibility mode?

I tried to extend the volume and it worked, without rebooting the VM.

But the round-robin does not work anymore. I will do some other testing today on this

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