Increase the storage size or change the storage location of the volume snapshot

Symptoms

Disk/partition or file-level backup fails with the following error:

Not enough space to create a volume snapshot on the volume where the snapshot storage is located.

or 

Not enough space to create a volume snapshot on the volume where the snapshot storage is set.

or

There is not enough space on the volume where the snapshot storage is located

or error in Windows event log

Event ID:  25
The shadow copies of volume G: were deleted because the shadow copy storage could not grow in time. Consider reducing the IO load on the system or choose a shadow copy storage volume that is not being shadow copied.

Cause

There is not enough space for the snapshot storage on the source disk.

Once a snapshot is created during backing up, all the subsequent I/O operations are cached in a temporary storage called snapshot storage. If the amount of I/O operations is too large, the space for caching them can end.

For more information about snapshots see Acronis Cyber Backup Creates a Temporary File During Snapshot

Solution

One of the ways to avoid this issue is to perform backups when the I/O load is lower.

You can also free up space on the source disk or move the storage to a volume with more free space (on server operating systems only).

Acronis uses the same drive to create a shadow copy by default if VSS is enabled. Moving VSS Shadow Storage can be useful if you need to:

• Use a different drive with more free space available to create a snapshot
• Distribute the snapshot I/O load to a different drive on production devices
• Perform a successful snapshot of a disk that may be damaged

Acronis Cyber Protect Cloud, Acronis Cyber Protect 15 and Acronis Cyber Backup 12.5

Microsoft VSS provider by default uses the same volume for storing snapshots with the small Maximum Shadow Copy Storage space parameter value.

The vssadmin command line tool should be used to check and configure the VSS storage parameters.

First you will need to list the shadow storages by using the vssadmin list shadowstorage command. See also Microsoft TechNet: Vssadmin list shadowstorage.

In the command line (Start-Run -> cmd), issue the following command:
vssadmin list shadowstorage

You will get the list of associations:

For volume: (C:)\\?\Volume{34e2a3b2-3136-11df-81bf-806e6f6e6963}\
Shadow Copy Storage volume: (C:)\\?\Volume{34e2a3b2-3136-11df-81bf-806e6f6e6963}\
Used Shadow Copy Storage space: 1.815 GB (1%)
Allocated Shadow Copy Storage space: 2.315 GB (1%)
Maximum Shadow Copy Storage space: 2.419 GB (1%)

(!) If no shadow storages are specified, the operating system defines the volume to store snapshots automatically.

On server operating systems you can change the current volume of where the storage is to a different one with the vssadmin delete shadowstorage and vssadmin add shadowstorage commands. This will delete the current shadow storage and create a new one on the volume you specify. See also Microsoft TechNet: Vssadmin delete shadowstorage and Vssadmin add shadowstorage.

For example:
vssadmin delete shadows /for=c:
vssadmin delete shadowstorage /for=c: /on=c:
vssadmin add shadowstorage /for=c: /on=d: /maxsize=20GB

As a result, all snapshot data of volume C: will be cached on volume D:.

You can also increase the maximum amount of storage space that can be used for shadow copy storage using the following command:

vssadmin resize shadowstorage

See Microsoft documentation for more details: vssadmin resize shadowstorage

Acronis Cyber Backup 11.7 and older versions

First, you need to check what snapshot provider is used:

1. 1. In Management Console or in Acronis Management Server go to Options -> Backup options;
   2. Go to Volume Shadow Copy section and check what snapshot provider is selected:

The solution depends on what snapshot provider is used

 

Software - System Provider (Microsoft VSS Provider)

Microsoft VSS provider by default uses the same volume for storing snapshots with the small Maximum Shadow Copy Storage space parameter value.

The vssadmin command line tool should be used to check and configure the VSS storage parameters.

First you will need to list the shadow storages by using the vssadmin list shadowstorage command. See also Microsoft TechNet: Vssadmin list shadowstorage.

In the command line (Start-Run -> cmd), issue the following command:

vssadmin list shadowstorage

You will get the list of associations:

For volume: (C:)\\?\Volume{34e2a3b2-3136-11df-81bf-806e6f6e6963}\
Shadow Copy Storage volume: (C:)\\?\Volume{34e2a3b2-3136-11df-81bf-806e6f6e6963}\
Used Shadow Copy Storage space: 1.815 GB (1%)
Allocated Shadow Copy Storage space: 2.315 GB (1%)
Maximum Shadow Copy Storage space: 2.419 GB (1%)

(!) If no shadow storages are specified, the operating system defines the volume to store snapshots automatically.

If the volume that you back up has enough free space to store the snapshots, you can resize the shadow storage with the vssadmin resize shadowstorage command. See also Microsoft TechNet: Vssadmin resize shadowstorage.

For example

vssadmin resize shadowstorage /for=c: /on=c: /maxsize=20GB

(!) If you would like to allocate all of the volume's free space for the storage, use the unbounded value. E.g. vssadmin resize shadowstorage /for=c: /on=c: /maxsize=unbounded

You can also do the resize via Computer -> Properties -> System Protection. For details please see External Resource: Change & Limit System Restore In Windows 7.

If you need to change the current volume of where the storage is to a different one, you can do this on server operating systems with the vssadmin delete shadowstorage and vssadmin add shadowstorage commands. This will delete the current shadow storage and create a new one on the volume you specify. See also Microsoft TechNet: Vssadmin delete shadowstorage and Vssadmin add shadowstorage.

For example

vssadmin delete shadowstorage /for=c: /on=c:
vssadmin add shadowstorage /for=c: /on=d: /maxsize=20GB

As a result, all snapshot data of volume C: will be cached on volume D:.

(!) Only server operating systems support the Shadow Copy transporting functionality.

Software - Acronis VSS Provider

Acronis VSS provider by default creates a temporary file in the %TEMP% folder of a user, under which a backup plan/policy is running. By default, the full path is:

• Windows 2000/XP/2003: \Documents and Settings\%username%\Local Settings\Temp
• Windows Vista/7/2008/2008 R2: \Users\%username%\AppData\Local\Temp

The default relative snapshot storage size is 20% of free space of the partition where it resides. If the amount of free space on the snapshot storage volume is enough the issue can be avoided by increasing the default relative size.

You can increase the storage size or move the storage to a different volume by following instructions in Acronis Cyber Backup Creates a Temporary File During Snapshot - there are instructions for both Windows and Linux.

More information

Troubleshoot VSS-related issues with the free Acronis VSS Doctor tool. If it didn't help, please contact Acronis Support.