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MattGoddard
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Arrgh! VM disk won't resize beyond 2 TB.

vSphere 5.5 U3b, Windows Server 2008 R2 VM (64-bit), running from an NFS volume on an EMC VNXe3150.

I powered down the VM, resized the (non-OS) disk from 2 TB to 3 TB, powered on the VM and attempted to extend the disk. However, the extend option was grayed out in Disk Manager.

I powered down the VM, booted into a GParted live CD and attempted to extend it that way, but got the following error: "...partition length of 6442448896 sectors exceeds the msdos-partition-table-imposed maximum of 4294967295". It's an NTFS disk in Windows, so I don't get what that "msdos-partition-table-imposed maximum" stuff is about. It should be able to extend way further than 3 TB.

Checking this KB, I should be able to extend this - as far as I can tell, it meets all the requirements.

Can anyone help me figure out the problem? There's an ever-growing customer folder on this disk and it's likely to fill up in a couple of days, which would be...bad!

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a_p_
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From what you explained, the issue is rather related to the guest OS partition table.

With an "MBR" partition table, partitions are limited to 2TB max. If you need larger partitions you need a "GPT" partition table.

For newer Windows versions (e.g. 2012R2, or Windows 10), Microsoft has a tool (mbr2gpt.exe) which can convert the partition table without data loss. I'm not sure whether this will work on Windows 2008R2 though. What may be worth trying is to run the tool using a boot CD/ISO with a newer OS, or checking whether gParted can do the job.

In any case, make sure that you create a snapshot (with the VM in powered off state), so that you can revert to the current state in case something goes wrong.


André

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4 Replies
a_p_
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From what you explained, the issue is rather related to the guest OS partition table.

With an "MBR" partition table, partitions are limited to 2TB max. If you need larger partitions you need a "GPT" partition table.

For newer Windows versions (e.g. 2012R2, or Windows 10), Microsoft has a tool (mbr2gpt.exe) which can convert the partition table without data loss. I'm not sure whether this will work on Windows 2008R2 though. What may be worth trying is to run the tool using a boot CD/ISO with a newer OS, or checking whether gParted can do the job.

In any case, make sure that you create a snapshot (with the VM in powered off state), so that you can revert to the current state in case something goes wrong.


André

ChrisFD2
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Yup - sounds like the guest OS is running an MBR disk.

Also, 5.5?! Get that upgraded!

Regards,
Chris
VCIX-DCV 2023 | VCIX-NV 2023 | vExpert *** | CCNA R&S
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continuum
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> Get that upgraded!

Whats wrong with "last known version with flawless GUI" ?


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MattGoddard
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Yep, that was the problem. I resolved it by using gptgen to convert the partition table to GPT. Instant fix! Now I can extend the disk no problem.

Thanks for the replies, folks!