Acronis software creates a temporary file during snapshot

If there is not enough storage space to create the temporary snapshot file, the backup operation will fail with an error message similar to the following one:

Not enough storage is available to process this command

This article describes what this temporary file is and how to modify its size. For detailed description of the snapshot process, see SnapAPI.

Note: in centralized backup plans the snapshot storage settings specified on the Management Server take precedence over Agent's snapshot storage settings.

Windows

Windows

Once a snapshot is created, Acronis Cyber Backup product creates a temporary file in the specified place. The name of the file is random, but is similar to acr74BD.tmp.

By default, the full path is:
Windows 2000/XP/2003: %ALLUSERSPROFILE%\Application Data\Acronis\BackupAndRecovery\MMS\Temp
Windows Vista/7/2008/2008 R2: %PROGRAMDATA%\Acronis\BackupAndRecovery\MMS\Temp
(Acronis Cyber Backup & Recovery 10 creates a temporary file in the %TEMP% folder of a user, under which a backup plan/policy is running)

This file is a container that has the snapshot image and receives all write operations from the system pending after the snapshot is created and before the backup creation completes.

This ensures that the created backup has the latest image of the system and that absolutely no piece of information is lost.

This temporary file is automatically deleted once the backup creation completes.

Changing default location and size of the cache:

When using Software System 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 allocates up to 10% of the volume the snapshot is taken of.

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.

If Volume Shadow Copy Service (VSS) snapshots do not get deleted automatically after the backup, you can delete them manually:

vssadmin Resize ShadowStorage /For=C: /On=C: /MaxSize=300MB (this will force the system to delete the snapshots)

vssadmin Resize ShadowStorage /For=C: /On=C: /MaxSize=10240MB (after deleting the snapshots, set a maximum size limit of the total storage area that the shadow copies can occupy)

When using Acronis VSS Provider

The size of this temporary file by default is exactly 20% of the free space of the partition where the temporary folder is.

Changing the default relative size of the file

The default relative size is 20% of the free partition space.

By decreasing the default relative size you risk that the backup creation will fail when there is not enough space in the file to receive all the pending write operations. This is not recommended if you have a loaded system.

By increasing the default relative size you ensure that the backup creation will not fail due to lack of space in the file, but at the same time you risk that there will not be enough space for other applications that might need it.

To change the default size, do the following:

Open Windows Registry Editor (Start-Run -> regedit);
Browse to the following subkey:
Acronis Cyber Backup Сloud/Acronis Cyber Backup 12.5/11.7/11.5:
- For local machine (or standalone edition): HKEY_LOCAL_MACHINE\SOFTWARE\Acronis\MMS\Configuration\Protection\Backup\SnapshotStorage
- When using centralized backup plan: HKEY_LOCAL_MACHINE\SOFTWARE\Acronis\AMS\Configuration\Protection\Backup\SnapshotStorage
  (!) Using centralized backup plan from Acronis Management Server overwrite the setting from local agent. See online help for more details.
Acronis Cyber Backup & Recovery 11:
- HKEY_LOCAL_MACHINE\SOFTWARE\Acronis\MMS\Configuration\Protection\Backup\SnapshotStorage
Acronis Cyber Backup & Recovery 10:
- Windows 32 bit: HKEY_LOCAL_MACHINE\SOFTWARE\Acronis\MMS\Configuration\Protection\Backup\SnapshotStorage
- Windows 64 bit: HKEY_LOCAL_MACHINE\SOFTWARE\Wow6432Node\Acronis\MMS\Configuration\Protection\Backup\SnapshotStorage
Double-click on RelativeSize and set the Value data to the one you choose:

In this example the relative size value is set to 70%.
Click OK.

Changing the storage path of the file

To change the default storage path, do the following:

Open Windows Registry Editor (Start-Run -> regedit);
Browse to the following subkey:
Acronis Cyber Backup Сloud/Acronis Cyber Backup 12.5/11.7/11.5:
- For local machine (or standalone edition): HKEY_LOCAL_MACHINE\SOFTWARE\Acronis\MMS\Configuration\Protection\Backup\SnapshotStorage
- When using centralized backup plan: HKEY_LOCAL_MACHINE\SOFTWARE\Acronis\AMS\Configuration\Protection\Backup\SnapshotStorage
  (!) Using centralized backup plan from Acronis Management Server overwrite the setting from local agent. See online help for more details.
Acronis Cyber Backup & Recovery 11:
- HKEY_LOCAL_MACHINE\SOFTWARE\Acronis\MMS\Configuration\Protection\Backup\SnapshotStorage
Acronis Cyber Backup & Recovery 10:
- Windows 32 bit: HKEY_LOCAL_MACHINE\SOFTWARE\Acronis\MMS\Configuration\Protection\Backup\SnapshotStorage
- Windows 64 bit: HKEY_LOCAL_MACHINE\SOFTWARE\Wow6432Node\Acronis\MMS\Configuration\Protection\Backup\SnapshotStorage
Double-click on StoragePath and in the Value data field provide the path where the temporary file should be created:

In this example the storage path is set to C:\SnapTMP:
Click OK.
Recreate the backup plan.

(!) If HKEY_LOCAL_MACHINE\SOFTWARE\Acronis\MMS\Configuration\Protection\Backup\SnapshotStorage\StoragePath contains incorrect address or points to a folder that does not exist, the backup task will fail with error Failed to create temporary file. Make sure that you specify valid address and that the target folder exists.

Linux

Linux

Once a snapshot is created, Acronis product on Linux does not create a temporary file.

The temporary file is created only if the size of the snapshot data exceeds 12500 snapshotted filesystem blocks (it is 50 MB for a typical ext3 partitions with 4 KB block size).

The temporary file is created in the following default folder:

/tmp

The name of the file is random, but is similar to acro_cache_XXXXXX.

If necessary, the size of this temporary file grows from zero until the size available on partition that keeps it.

Changing the storage path of the file

Temporary file location may be changed via setting the special environment variable ACRONIS_SNAPSHOT_TMP_DIR applied to process creating snapshot (typically it is BackupAndRecoveryService or TrueImageCmd). To set up this variable for all Acronis programs, it is recommended to add it into the config file:

For Acronis Cyber Protect Cloud / Acronis Cyber Backup 12.5: by default config file does not exist. Create the file manually:

# touch /usr/lib/Acronis/system_libs/5.3.0/config

For Acronis Cyber Backup & Recovery 10 choose the config file here: /usr/lib/Acronis/system_libs/config file;

For Acronis Cyber Backup 11.7/11.5 and Acronis Cyber Backup & Recovery 11 choose the config file here:

for 64-bit: /usr/lib/Acronis/BackupAndRecovery/system_libs64

for 32-bit: /usr/lib/Acronis/BackupAndRecovery/system_libs

For example:

WRAPPER=
export ACRONIS_SNAPSHOT_TMP_DIR=/var/tmp

How to get the config file path

In fact, you need not to remember exact "config" file path.
If you type content of any our program wrapper script, for example
/usr/sbin/acronis_mms, you'll see:

[root@RHEL52x64 ~]# cat /usr/sbin/acronis_mms
#!/bin/bash

[ -r /usr/lib/Acronis/BackupAndRecovery/system_libs64/config ] && . /usr/lib/Acronis/BackupAndRecovery/system_libs64/config

If the config file does not exist

If the file is absent it is necessary just create it in any text editor, vi, gedit, etc.

After making the changes in the config file please make sure to restart acronis services for the changes to take effect:

- - # /etc/init.d/acronis_mms restart
  - # /etc/init.d/acronis_agent restart

More Information

As we see the script checks "config" file presence and "source"(executes) it if it exists.
The file is useful not only as place for ACRONIS_SNAPSHOT_TMP_DIR environment variable - other variables may be set here.
You need to open/create the file, add line ACRONIS_SNAPSHOT_TMP_DIR=DIRECTORY_NAME and save the file.

Knowledge Base

8032: Acronis software creates a temporary file during snapshot

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