Limitation for increasing a volume beyond 2 TB on a single disk

Description

Error Message

There are no error messages reported. However, the state of the disks for the impacted volume(s) will be reported as below:

Missing Disk (Disk ###)

Cause

When expanding or creating a volume, the volume size is as important as the layout of the volume. When using a Master Boot Record (MBR) volume type, expanding the volume on a single disk beyond 2 TB will cause the volume to show up as corrupted.

This is due to a limitation in the MBR volume type as it cannot be used beyond the 2 TB threshold.

Additionally, as Veritas Infoscale uses the last 16 MB of a disk to create a Private Region (PR) for Dynamic and Cluster Dynamic Disk Groups, if the volume size exceeds 2 TB, the PR can no longer be read, thereby causing the disk(s) to report as missing.

Resolution

Within the Windows Server Operating Systems, there is a limitation in the Master Boot Record (MBR) format that does not allow for a single volume on a single disk to grow more than 2 TB.

However, using Veritas Infoscale for Windows, the above limitation can be avoided by allowing the volume to span across multiple disks by following the below steps:

1) From VEA, add a new disk to the Diskgroup containing the impacted volume(s) using the Add Disk to Dynamic Disk group option.

2) If there is a need to expand the volume, then right click on the volume, select Resize Volume -> Expand ..

Now enter the size and this time, it can be beyond 2 TB.

3) If there is a need to create a new volume of more than 2 TB, then right click on the Diskgroup and select Create Volume -> Select Disks -> Enter size -> Finish

NOTE: In the above step, ensure to select multiple disks to avoid the 2 TB MBR limitation.

OR

If multiple disks cannot be made available, a new single disk can be established with a GUID Partition Table (GPT) using the below steps, which will allow for a single volume on a single Disk to grow well beyond the 2TB limitation.

a) Present a new disk to the Server.

b) From VEA, right click on the disk and select Online Disk

c) Once the disk is online, right click on the disk and select Write Signature.

d) In the Write Signature Wizard, select the option GUID Partition Table (GPT) and finish the wizard.

e) Now create a Diskgroup using this disk followed by a volume using Step #3 listed above.

For more information on GPT disks, please review the Microsoft article: Windows and GPT FAQs

Issue/Introduction

For Veritas Infoscale on a Windows platform, if a volume size exceeds 2 TB on a single disk, it causes the disk for that volume to appear as missing in Veritas Enterprise Administrator (VEA)

Error Message

There are no error messages reported. However, the state of the disks for the impacted volume(s) will be reported as below: Missing Disk (Disk ###)

Cause

When expanding or creating a volume, the volume size is as important as the layout of the volume. When using a Master Boot Record (MBR) volume type, expanding the volume on a single disk beyond 2 TB will cause the volume to show up as corrupted. This is due to a limitation in the MBR volume type as it cannot be used beyond the 2 TB threshold. Additionally, as Veritas Infoscale uses the last 16 MB of a disk to create a Private Region (PR) for Dynamic and Cluster Dynamic Disk Groups, if the volume size exceeds 2 TB, the PR can no longer be read, thereby causing the disk(s) to report as missing.

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