This article describes an update to improve the Microsoft Azure Backup performance. Before you install this update, see the Prerequisites section. Additional steps for configuration are required to enable this update after the installation.
Symptoms
The incremental backups by using the Azure Backup agent may run slowly for servers that have many files.
Resolution
To fix this problem, install the latest version of the Microsoft Azure Recovery Services agent.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 Center
The following file is available for download from the Microsoft Download Center:
Update information
Prerequisites
To apply this update, you must have Azure Backup agent installed.
Restart information
You may have to restart the computer after you apply this update.
Replacement information
This update replaces the previously released update 3080243.
Additional configuration steps
Registry information
After 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 restorationin case problems occur.
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In Registry Editor, locate and then select the following registry subkey:HKEY_LOCAL_MACHINE\Software\Microsoft\Windows Azure Backup\Config\CloudBackupProvider
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Press and hold (or right-click) CloudBackupProvider, point to New, and then click DWORD (32-bit) Value.
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Name the new registry entry as UseUsnIterator.
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Double-click the UseUsnIterator registry entry.
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In the Edit DWORD Value dialog box, enter 1 in the Value data field, and then click OK.
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Exit Registry Editor.
Note To turn off the performance fixes, set the values to 0.The new registry entry should resemble the entry in the following screen shot.
Increase default size of USN journal
The 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 command output resembles the following screen shot:
fsutil usn createjournal m=67108864 a=8388608 C: Note Run this command for all volumes that are being protected.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 |
Status
Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.
References
Learn about the terminology that Microsoft uses to describe software updates.
