Symptoms
- You create a backup to a destination formatted in NTFS
- Backup (or another operation, e.g. applying retention rules) fails with one of the following errors:
Windows error: (0x80070299) The requested operation could not be completed due to a file system limitation
or
Cannot write data to file <path> due to a file system limitation. The disk may be highly fragmented or the file is too large
Cause
There are two possible causes:
- Disk is highly fragmented so that when data is written to the archive, it hits file system limitation
- Archive format uses sparse files - fragmented files that contain holes, which do not occupy physical disk space. In combination with native file system fragmentation, large backup file that contains a lot of sparse files, hits file system limitation and backup fails with the error.
Solution
- In Backup Options -> Splitting enable fixed size split backup and set slice size between 100GB and 500GB, and create a new backup archive.
(!) Splitting option is not available for Always incremental backup scheme. See Splitting for details.
Splitting option is also not available if Cloud storage is specified as a secondary location. In this case, it is recommended to create separate backup plans: one with splitting, for local storage, and a second one for backing up to Cloud
- Free up additional space on the disk or add storage capacity
If the backup destination is Acronis Storage Node, then backup splitting is not supported. In this case, there are 2 possible solutions:
- Use a network share instead of Storage Node and activate splitting in backup plan as described earlier.
- Resolve the problem with fragmentation on the target disk.
More information
In case you are specially preparing storage with NTFS file system for storing large backups, for better handling of large files it is recommended to set a 64 KB NTFS allocation unit size and enable support for large file record segments (FRS) on the partition: see Formatting requirements for large files in this document for more information.