Azure Backup performance update
Additionally, add a registry entry that's described in the "Registry information" section, and follow the instructions in the "Increase default size of USN journal" section to increase the default size of the USN journal in the volumes that are being protected.
Download CenterThe following file is available for download from the Microsoft Download Center:
Note The latest version of the Microsoft Azure Recovery Services agent is 2.0.8724.0.
PrerequisitesTo apply this update, you must have Azure Backup agent installed.
Restart informationYou may have to restart the computer after you apply this update.
Replacement informationThis update replaces the previously released update 3080243.
Additional configuration steps
Registry informationAfter you install this update, you must add the following registry entry.
Important Follow the steps in this section carefully. Serious problems might occur if you modify the registry incorrectly. Before you modify it, back up the registry for restoration in case problems occur.
- In Registry Editor, locate and then select the following registry subkey:HKEY_LOCAL_MACHINE\Software\Microsoft\Windows Azure Backup\Config\CloudBackupProvider
- Press and hold (or right-click) CloudBackupProvider, point to New, and then click DWORD (32-bit) Value.
- Name the new registry entry as UseUsnIterator.
- Double-click the UseUsnIterator registry entry.
- In the Edit DWORD Value dialog box, enter 1 in the Value data field, and then click OK.
- Exit Registry Editor.
The new registry entry should resemble the entry in the following screen shot.
Increase default size of USN journalThe performance fixes that are provided in this update use the USN Journal in Windows. By default, Windows allocates only a small amount of space for the USN Journal. We recommend that you increase the default space that is allocated for the USN Journal based on the number of files that are being protected.
To check the current value that is set for USN, run the following command at an elevated command prompt:
fsutil usn queryjournal C:
The hex value for "Maximum Size" (0x000000000200000) indicates that the current space that's allocated for the USN Journal is 2 MB.
You can increase the space that is allocated for the USN Journal by setting the Maximum Size and the Allocation Delta. The allocation delta is typically one-eighth of the Maximum Size.
Run the following command at an elevated command prompt:
fsutil usn createjournal m=67108864 a=8388608 C:
The following table contains the values to be set, based on the number of files that are being protected.
|Files||Maximum Size (m) in bytes||Allocation Delta (a) in bytes|
|1 000 000||1 342 177 280||167 772 160|
|1 200 000||1 610 612 736||201 326 592|
|1 600 000||2 147 483 648||268 435 456|
|2 000 000||2 684 354 560||335 544 320|
|2 400 000||3 221 225 472||402 653 184|
|2 800 000||3 758 096 384||469 762 048|
|3 200 000||4 294 967 296||536 870 912|
Article ID: 3090067 - Last Review: 10/20/2015 22:06:00 - Revision: 5.0
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