Please Help, Disk Full of Data to Import on XenServer VM of FreeNAS

[tyh-chris]

Hi,

I'm running an installation of FreeNAS on XenServer 7.0, emulating a disk to share via iSCSI.

Long story short, the VDI ended up being detached from the VM while it was moving to another XenServer host. When I reattached it, FreeNAS sees the disk, but not the volume / pool. I can't run the import because that doesn't handle ReFS.

I know the data is there and unscathed, but I can't get FreeNAS to recognise it.

Any ideas?

Thanks

 

[depasseg]

When I reattached it, FreeNAS sees the disk, but not the volume / pool. I can't run the import because that doesn't handle ReFS.

You are confusing me. What are you reattaching where? And why would FreeNAS need to handle ReFS?

 

[tyh-chris]

Thanks for the reply.

I am reattaching the virtual disk with all my data to the FreeNAS virtual machine via XenCenter. However, for whatever reason, FreeNAS does not recognise the virtual disk any longer. If I visit the Storage tab in the FreeNAS web interface, there is a reference to pool1, but it says there's an error getting the available space, and the status is "UNKNOWN". If I click on Volume Manager I can see the disk, but I can only create a new volume on it which as you know will wipe it.

Import Disk doesn't work for me as the only file systems it supports are UFS, NTFS, MSDOSFS and EXT2FS, whereas the filesystem I was using on this disk was ReFS.

Import Volume doesn't show any volumes to import at step 2, so I can't use that either.

 

[darkwarrior]

Hi there,

indeed you are mixing up many things...
I'm guessing you are trying to say that you were having a pool attached to FreeNAS, that was hosting a zVOL, shared out via iSCCI, on which you was having a ReFS partition.

How were the disks attached to the FreeNAS VM prior to the move ? You were using (I hope) PCI Passthrough ?
If you were using a Virtual Disk equivalent in XenServer and were hoping that you would be able to move it with the VM just like this you might just have gotten involved into a traincrash...

 

[tyh-chris]

I wasn't using PCI Passthrough, it was a virtual disk file. I know that it's best for FreeNAS to have direct access to physical disks so that it can work its magic with RAID, but all I was using it for was iSCSI.

I suppose I'd just like to know why FreeNAS no longer recognises the pool. I restored a cloud backup of the data over the weekend, so that's not a problem, but it would be nice to understand what happened.

 

[darkwarrior]

Ah, I'm glad to hear that you had a backup of all your data :)

Concerning your specific problem, just guessing into the void:
It could be that when you moved the VM and the Virtual disk and you fired up the VM, XenServer actually remapped the disk and FreeBSD recognized it as a new disk and thus assigned a new GPT Id.
Disaster followed soon as the FreeNAS middleware tried to import the pool, but in the pool description was a different GPT ID mentioned. Followed by the inability to mount the pool or to recognize the actual size.

Bad things always happen when you're not following good practices ...
You seem to know one of the best practices concerning FreeNAS and VMs, so I'm wondering why you created a single disk stripe on top of a Virtual Disk file ??
Especially for data that you seem to care about, since you had a full off-site backup.

 

[anodos]

I have not heard many success stories of people running FreeNAS on Xenserver. I believe the preferred virtualization solution (with caveats that you can read up on in the forums) is vmware.

 

[tyh-chris]

anodos: Interesting. After spending some time with XenServer I find it a lot more "fiddly" than VMWare's offerings. It seems very easy to break things.

darkwarrior: That certainly sounds plausible. XenServer uses a VBD (Virtual Block Device) to connect a VDI (Virtual Disk Image) to a VM. I think in this scenario, the VBD changed when the VDI was added to the virtual machine again, so FreeBSD saw a new disk as you said.

The reason for creating a FreeNAS VM in this manner was down to juggling data between two servers: I needed more storage space for my Windows Server VM, and so I created the FreeNAS VM on a host that had some spare, and accessed it via iSCSI. I guess it was a half experiment, too, with me feeling relatively safe in the knowledge that I was backing up off-site.

 

[depasseg]

Import Disk doesn't work for me as the only file systems it supports are UFS, NTFS, MSDOSFS and EXT2FS, whereas the filesystem I was using on this disk was ReFS.

Import Disk is when you want to copy data from a UFS, NTFS, MSDOSFS or EXT2FS disk. It's not when you want to add a pool (Volume). If your pool/volume isn't being detected and the correct virtual disk is attached, then I suspect the problem has to do with Xen.

 

[tyh-chris]

Ah, I see. Good to know, thanks.