When using Acronis Storage Node and deduplication on NTFS filesystem an error occur due filesystem limitation. To fix the issue, reduce the fragmentation by copy forth and back the deduplication storage (datastore) unified_data.ds.0/1.

This article applies to:

• Acronis Backup & Recovery 11.5 (Advanced Editions)
• Acronis Backup & Recovery 11 (Advanced Editions)

Symptoms

You are using deduplication feature for your backups and get this error in logs:

The requested operation could not be completed due to a file system limitation

See full error log:

Log Entry Details
--------------------
Type: Error
Date and time: 10/4/2012 1:22:06 PM
Backup plan: [None]
Task: [None]
Code: 20,250,685(0x135003D)
Module: 309
Owner: abr
Message:
Command 'Indexing vault' has failed.
Additional info:
--------------------
Error code: 61
Module: 309
LineInfo: 4a8728dc8a1c950f
Fields: $module : storage_server_vsa64_32256
Message: Command 'Indexing vault' has failed.
--------------------
Error code: 123
Module: 39
LineInfo: 8ed4fba2a46c475c
Fields: $module : storage_server_vsa64_32256
Message: Failed to index backup data '4CF8B5E3-6D61-4012-9940-053C10EA275C' from vault 'ru-2-managed-dedup'.
--------------------
Error code: 116
Module: 39
LineInfo: aeb34f528199bc89
Fields: $module : storage_server_vsa64_32256
Message: Failed to save the items.
--------------------
Error code: 33
Module: 39
LineInfo: f7d1612d6b579caf
Fields: $module : storage_server_vsa64_32256
Message: Storage node error.
--------------------
Error code: 98
Module: 39
LineInfo: aeb34f528199bc4f
Fields: $module : storage_server_vsa64_32256
Message: Data store transaction has failed.
--------------------
Error code: 7
Module: 4
LineInfo: 940c36e2778de93
Fields: $module : storage_server_vsa64_32256
Message: Failed to open data store 'Y:\ru-2-managed-dedup\unified_data.ds.0'.
--------------------
Error code: 7
Module: 4
LineInfo: 795414836ed3adb1
Fields: $module : storage_server_vsa64_32256
Message: Error occurred while opening the file.
--------------------
Error code: 7
Module: 4
LineInfo: 795414836ed3ac51
Fields: $module : storage_server_vsa64_32256
Message: Error occurred while opening the file.
--------------------
Error code: 3
Module: 4
LineInfo: 7ceb2cdc9fb120ae
Fields: function : SetEndOfFile, $module : storage_server_vsa64_32256
Message: Error occurred while writing the file.
--------------------
Error code: 65520
Module: 0
LineInfo: bd28fdbd64edb8e0
Fields: code : 2147943065, $module : storage_server_vsa64_32256
Message: The requested operation could not be completed due to a file system limitation
--------------------
Acronis Knowledge Base: http://kb.acronis.com/errorcode/

Event code: 0x0135003D+0x0027007B+0x00270074+0x00270021+0x00270062+0x00040007+0x00040007+0x00040007+0x00040003+0x0000FFF0+0x80070299
-------------------

Cause

The used NTFS filesystem has some internal limitations. The important limitation here is the number of fragments for a single file. In this case the datastore file could become large enough and get to much fragments.

Solution

In Acronis Backup & Recovery 11 (Build 17318 or earlier) use one of the following workarounds: 

1. Copy forth and back the datastore files:
   1. Go to Start -> Run -> services.msc -> and stop Acronis Storage Node service;
   2. Search for this files: unified_data.ds.0 and unified_data.ds.1 and copy them to another place;
   3. If copy has been finished, copy them back to the original destination;
   4. Go to Start -> Run -> services.msc -> and start Acronis Storage Node service;
2. Backup and restore the datastore files:
   1. Go to Start -> Run -> services.msc -> and stop Acronis Storage Node service;
   2. Perform image backup of volume;
   3. Perform image restore of volume;
   4. Go to Start -> Run -> services.msc -> and start Acronis Storage Node service;

In Acronis Backup & Recovery 11 (Build 17437 or later) and Acronis Backup & Recovery 11.5 use this solution:

Starting from this builds Acronis has implemented pre allocation ability, so the data store files increased with large portions of data, so it has less fragments. The default pre allocation size is 512 MB. For large data store size (e.g. 11 TB) this is not enough. You need to adjust the pre allocation size manually according to the data size planned to be stored in the vault.

To set up pre allocation size follow these steps:

1.  Go to Start -> Run -> services.msc -> and stop Acronis Storage Node service;
2. Go to Start -> Run -> regedit.exe to open Windows registry editor and navigate to this key:
    
   HKEY_LOCAL_MACHINE\SOFTWARE\Acronis\ASN\Configuration\StorageNode\PreallocatedDatastoreIncrementSize
    
3. Change the default value (is 512 in megabytes). If you plan having more than 10 Tb of unique data size it's recommended to set PreallocatedDatastoreIncrementSize to 1024;
4. Go to Start -> Run -> services.msc -> and start Acronis Storage Node service;

More information

See also:

• Acronis Backup & Recovery 11.5
• Acronis Backup & Recovery 11.5: Editions