Frequently Asked Questions

General

Backup operation is slow. How do I troubleshoot the slowness?

If you are experiencing performance issues during backup, you can troubleshoot them by enabling logging of performance details in the log files. These performance counters contain information that help in resolving the performance related issues during backups. The performance reports are generated and available at the following location on the MediaAgent computer:

• <software_installation_path>\Log Files\ResourceMonitor\PerfLog_CommVaultJobsStreamStats-1.0.csv

• <software_installation_path>\Log Files\CVPerfMgr.log

For more information on viewing log files, see Viewing the Log Files of an Active Job.

Performance counters printed in the log files include:

The CVPerfMgr log file displays the time taken by a particular process. For example, a log snippet may look as follows:

 
|*4*|*Perf*|13| -----------------------------------------------------------------------------------------
 |*4*|*Perf*|13| Perf-Counter                             Time(seconds)      Size
 |*4*|*Perf*|13| -----------------------------------------------------------------------------------------
 |*4*|*Perf*|13| 
 |*4*|*Perf*|13| Windows File System Agent
 |*4*|*Perf*|13| |_Buffer allocation.......................... 144           

 |*4*|*Perf*|13| |_Read....................................... 156   5230734248 [4.87 GB] [112.42 GBPH]
 |*4*|*Perf*|13| |_Pipeline write............................. 69   5230942882 [4.87 GB] [254.18 GBPH]
 |*4*|*Perf*|13| |_Open File.................................. -           

 |*4*|*Perf*|13| |_FSDM Load Library.......................... -           

 |*4*|*Perf*|13|

You can also check the scan performance counters that are generated and available at the following location on your client computer:

You can also check the scan performance counters that are generated and available at the following location on your client computer:

<software_installation_path>\Log Files\FileScan.log

The FileScan log file displays the time taken for the scan operation. For example, a log snippet may look as follows:

5136 10bc 07/27 11:32:58 21077 Find::PostExecuteScan_Statistics(5449) - Total time for Optimal Scan (Data Classifier): 103.374705
 5136 10bc 07/27 11:32:58 21077 Find::PostExecuteScan_Statistics(5450) - Generating tables: 4.885698
 5136 10bc 07/27 11:32:58 21077 Find::PostExecuteScan_Statistics(5451) - QueryCallback: 0:20.619982, 241348 samples, 0:00.000085 average, 11704/second
 5136 10bc 07/27 11:32:58 21077 Find::PostExecuteScan_Statistics(5452) - QueryIteration: 0:03.818934, 241357 samples, 0:00.000015 average, 63200/second
 5136 10bc 07/27 11:32:58 21077 Find::PostExecuteScan_Statistics(5456) - IsFileFilteredOut: 0:05.813762, 241354 samples, 0:00.000024 average, 41514/second
 5136 10bc 07/27 11:32:58 21077 Find::PostExecuteScan_SetJobInfo(5508) - Found 642 files and 391 folders (1033 total items) to back up
 5136 10bc 07/27 11:32:58 21077 Find::PostExecuteScan_SetJobInfo(5538) - Updated TotalBytesToBackup Perfctr, TotalBytesToBackup=[0]

Recommendations:

• If multiple reads are enabled on the disk, verify that the hardware you use supports multiple reads else enabling multiple reads might degrade the disk read performance.

• You can use Raid disks or disks that allow multiple simultaneous reads which improves the performance of the backup job.

Why is IIS (Internet Information Server) not restored during a full system recovery?

When an operating system is re-installed , IIS is not installed again. After a full system restore, IIS would fail to start or open in Internet Services Manager or Computer Management because the old keys are not replaced by the new keys.

Uninstall and Re-install IIS to resolve this issue.

Why are my incremental backups same size as that of full backup?

Incremental backups may be the same size as that of a full backup due to any one of the following reasons:

1. A third party software or antivirus scanner installed on your system is modifying the files every time they are backed up. In this process, these files are picked up in the subsequent backups increasing the size of incremental backups.

Oracle Fusion Middleware (OFM) is configured on your computer with incorrect settings. This could prevent the directory change rename after the full backup. This could also result in synthetic full backup failure.

1. Backups are performed from a Snap (hardware snap, QSnap, VSS snap) or other read-only location such as a NetApp mirror using recursive scan method with Check archive bit during backups option enabled. Selecting Check archive bit during backups picks up all the files from the snap for backup. FAT volumes and volumes with mount points that do not have an associated volume letter would also be picked up for backup.

   As a workaround, change the scan method to Change Journal or disable Check archive bit during backups option in the Subclient Properties dialog box.

How will I view the files that were skipped during backup?

Certain files found during scan phase might be missing during backup. By default, the backup job skips these missed files during backup so that these files are not counted as failed objects. However, if you do not want these missing files to be skipped during backup, enable nDoNotSkipMissingFilesOnBackupadditional setting. Additionally, these missing files will be counted as failed objects.

Why restoring data from NTFS to ReFS volumes fail?

The user might receive an error when restoring data from a local NTFS (New Technology File System) to a local ReFS (Resilient File System) volume. This is because restore files with alternate data streams under 128 KB are not supported.

WFS0022: Why am I prompted to reboot the computer after performing a restore operation?

After a file system or a System State restore, you may be prompted to reboot the computer to which the data was restored. This is because the data that was attempted to be rebooted was in use or locked by another process.

In such cases, the following is observed:

1. The file is restored into the same directory. For example, filename.txt would be restored as ~filename.txt~ in the same directory.

2. An entry for this file is created in the PendingFileRenameOperations key in the registry.

At the end of the restore operation, the restore process will report to the CommServe that the system must be rebooted which in turn would display message in the CommCell Console to reboot the computer.

When the server is rebooted, Microsoft Windows operating system will overwrite the locked files with the temporary files created in the PendingFileRenameOperations registry key.

For more information on PendingFileRenameOperations, see Microsoft KB 181345.

For more information on a third party tool made by Microsoft that will show the pending files to be renamed, see Microsoft Windows Sysinternals.

What is the procedure to delete the Optimized Scan database on Windows?

The Optimized Scan database is available on every volume. If you have multiple volumes, perform the following steps to delete the database manually from each volume.

1. Stop the services on the client machine.

2. Download third-party PsExec tool.

3. At the command prompt, type the following:

   psexec -i -s cmd

   This opens a new command prompt window.

4. Delete the database dc_<instance_number>.db from its location. Usually, the database is available at the following location:

   System Volume Information\CommVault \Data Classification

   Enter the following in the new command prompt:

   C:\System Volume Information\CommVault\Data Classification>del dc_002.db

   where C:\ is the drive where the database is located and dc_002.db is the database to be deleted.

Block-Level Backups

How do we estimate the required free space for extent recovery location?

The amount of free space needed for the extent recovery location is roughly the amount of files selected in the browse plus a percentage of overhead. Overhead estimation is dependent on the amount of fragmentation associated with the volume as originally protected via the Image Level backup.

Example1: If the default extent size is 1MB, in order to restore a 4KB file, a 1 MB extent is restored on the client to allow for the extraction of the 4KB file.

Example 2: A 400KB file is highly fragmented and scattered in 100 different extents. All 100 extents (100MB) will need to be restored to the machine to restore the 400KB file.

Can we run block-level backups on the ReFS volumes if Windows deduplication is enabled on the source client computer?

If you have enabled Windows deduplication on the source client computer, you cannot run block-level backups on the ReFS (Resilient File System) volumes.