When sizing the USN journal, use 128 MB for every 100,000 files
on the volume. If files on the volume are changed or renamed
frequently (regardless of whether they are part of the replica
set), consider sizing the USN journal larger than these
recommendations to prevent USN journal wraps, which can occur when
large numbers of files change so quickly that the USN journal must
discard the oldest changes (before FRS has a chance to detect the
changes) to stay within the specified size limit. To recover from a
journal wrap, you must perform a nonauthoritative restore (also
called a D2) on the server to synchronize its files with the files
on the other replica members.
When determining the USN journal size, also consider the
Multiple replica trees can exist on the same NTFS volume.
Therefore, choose a USN journal size based on the total number of
files managed by FRS on that volume.
Other files might also be stored on the same NTFS volume, and
file operations on these files are tracked in the USN journal, even
though FRS ignores these changes. As a general guideline, add an
extra 8 MB per 100,000 files in this case, though this is an
approximate number that depends on how much activity occurs on
For best results, put replica trees on their own NTFS volume
(or volumes) so that other file activity does not affect the USN
journal on the volumes storing replica trees.
Use the following procedure to adjust the USN journal size. Note
that the USN journal size applies to all volumes on the server.
To change the USN journal size
In the Run dialog box, type regedit.exe, and
Right-click the Parameters subkey and choose New
-> DWORD Value.
Type NTFS journal size in MB as the new value name and
Right click NTFS journal size in MB and click Modify.
Click Decimal, and then in the Value data field,
type the size in megabytes that you would like to make the NTFS
Click OK, and then close the Registry Editor.
At the command prompt, type net stop ntfrs & net start