VMware Restore Operation Fails with Read-Only Error When Using SAN Transport Mode

A restore of a VMware VM that uses SAN transport mode fails if the VSA proxy is in read-only mode.

Symptoms

A restore operation for a VMware VM fails when using SAN transport mode. The following JPR appears:

Unable to write data to virtual disk [[DS] vm_name.vmdk] using SAN transport because it is read only.  Ensure that the access node has write access to physical disk [disk_identifier].

Where disk_identifier is in the form [\.\PhysicalDisknn] for a Windows proxy (nn is the disk number) or [/dev/sdxx]  for a Linux proxy (sdxx is the device name).

Causes

A restore that uses SAN transport mode fails if the VSA proxy is in read-only mode.

Resolution

Clear the read-only mode on the VSA proxy machine by performing the appropriate steps, based on the operating system type (Linux or Windows). Linux machines:

1. Open a shell.
2. Run this command: sudo /sbin/blockdev --setrw /dev/sdxx

In place of /dev/sdxx, use the name of the device or devices that were listed in the error message.

Windows machines:

1. Open a command prompt.
2. Run diskpart.
3. Select the SAN shared disk by typing select disk nn, where nn is the disk number that was listed in the error message as \.\PhysicalDisknn.
4. Type attribute disk clear readonly.

For example:

C:\Users\Administrator> diskpart

Microsoft DiskPart version 6.0.6002 Copyright (C) 1999-2007 Microsoft Corporation. On computer: COMPUTERNAME

DISKPART> list disk

Disk ### Status Size Free Dyn Gpt -------- ---------- ------- ------- --- --- Disk 0 Online 64 GB 0 B Disk 1 Offline 78 GB 2048 KB <--- The share disk is usually reported as Offline

DISKPART> select disk 10

Disk 10 is now the selected disk.

DISKPART> detail disk

ROCKET IMAGEFILE SCSI Disk Device Disk ID: 02872505 Type : iSCSI Bus : 0 Target : 0 LUN ID : 0 Read-only : Yes <--- Make sure of read-only mode Boot Disk : No Pagefile Disk : No Hibernation File Disk : No Crashdump Disk : No

There are no volumes.

DISKPART> attribute disk clear readonly

Disk attributes cleared successfully.