Expanding a VDisk that is mapped to a Microsoft Windows host using the CLI

You can use the command-line interface (CLI) to dynamically expand the size of a virtual disk (VDisk) that is mapped to a Microsoft® Windows® host.

Perform the following steps to expand a VDisk that is mapped to a Windows host:

Issue the following CLI command to expand the VDisk:
```
svctask expandvdisksize -size disk_size -unit 
	b | kb | mb | gb | tb | pb vdisk_name/vdisk_id  
```
where disk_size is the capacity by which you want to expand the VDisk, b | kb | mb | gb | tb | pb is the data unit to use in conjunction with the capacity and vdisk_name/vdisk_id is the name of the VDisk or the ID of the VDisk to expand.
On the Windows host, start the Computer Management application and open the Disk Management window under the Storage branch.

You will see the VDisk that you expanded now has some unallocated space at the end of the disk.

You can expand dynamic disks without stopping I/O operations in most cases. However, in some applications the operating system might report I/O errors. When this problem occurs, either of the following entries might be recorded in the System event log:

Event Type: Information
Event Source: dmio
Event Category: None 
Event ID: 31 
Description: dmio: 
Harddisk0 write error at block ######## due to
disk removal

Event Type: Information
Event Source: dmio
Event Category: None
Event ID: 34 
Description: dmio:
Harddisk0 is re-online by PnP

Attention: This is a known problem with Windows 2000 and is documented in the Microsoft knowledge base as article Q327020. If either of these errors are seen, run Windows Update and apply the recommended fixes to resolve the problem.

If the Computer Management application was open before you expanded the VDisk, use the Computer Management application to issue a rescan command.

If the disk is a Windows basic disk, you can create a new primary or extended partition from the unallocated space.

If the disk is a Windows dynamic disk, you can use the unallocated space to create a new volume (simple, striped, mirrored) or add it to an existing volume.