Track log sizing considerations

The accelerator track log stores file system metadata, and the unique fingerprints of files (128KiB segments). The track log size is relative to the size of the file system, and the number of backup files. Different track logs are created for each policy, client, and stream combination.

Here are some general guidelines, but the requirements in a specific environment might be different. Environments with a high rate of data change may require a larger track log size.

For D-NAS policy, the track log is stored on the backup host, and transferred to the primary server in-line during the backup operation. You can use the following formula to calculate the approximate size:

Total Track log size in Bytes for a NAS volume backup job = 2*( (Number of files * 200) + ((Total used disk space in KiB/128KiB) * 20))

For example, 1 TB NAS volume with one million files = ~ 701 MiB total track log size. If four streams are configured for backup and one million files are equally distributed amongst four streams, then each stream's track log can be ~175 MiB in size.