Evaluating System Components

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Evaluating Performance

There are two primary locations from which NetBackup data throughput performance statistics can be obtained for a NetBackup operation: the NetBackup Activity Monitor and the NetBackup All Log Entries report. The choice of which location to use is determined by the type of NetBackup operation you are measuring: non-multiplexed backup, restore, or multiplexed backup.

You can obtain statistics for all three types of operations from the NetBackup All Log Entries report. You can obtain statistics for non-multiplexed backup or restore operations from the NetBackup Activity Monitor (statistics for restore operations are newly available in the Activity Monitor with the 4.5 release). For multiplexed backup operations, you can obtain the overall statistics from the All Log Entries report after all the individual backup operations which are part of the multiplexed backup are complete. In this case, the statistics available in the Activity Monitors for each of the individual backup operations are relative only to that operation, and do not reflect the actual total data throughput to the tape drive.

There may be small differences between the statistics available from these two locations due to slight differences in rounding techniques between the entries in the Activity Monitor and the entries in the All Logs report. Therefore, we suggest you pick one location from which to obtain statistics and consistently use it to compare performance between test runs.

Evaluating Performance Through the NetBackup Activity Monitor

  1. Run the backup or restore job (restore job statistics available only in the 4.5 release).

  2. Open the NetBackup Activity Monitor.

  3. Verify the backup or restore job completed successfully. A 0 should appear in the status column.

  4. View the details for the job by selecting the Details menu option, or by double-clicking on the entry for the job.

  5. Select the Detailed Status tab.

  6. Obtain the NetBackup performance statistics from the following fields:

    • Started/Ended: These fields show the time window during which the backup or restore job took place.

    • Elapsed: This field shows the total elapsed time from when the job was initiated to job completion and can be used as an indication of total wall clock time for the operation.

    • KB/sec: This is the data throughput rate.

    • Current Kilobytes Written: Compare this value to the amount of data. Although it should be comparable, the NetBackup data amount will be slightly higher because of administrative information, known as metadata, saved for the backed up data.

      For example, if you display properties for a directory containing 500 files, each 1 MB in size, the directory shows a size of 500 MB, or 524,288,000 bytes, which is equal to 512,000 KB. The NetBackup report may show 513,255 KB written, reporting an extra 1,255 KB than provided through viewing the directory's properties. This is true for a flat directory. Subdirectory structures may diverge due to the way the operating system tracks used and available space on the disk. Also, be aware that the operating system may be reporting how much space was allocated for the files in question, not just how much data is actually there. For example, if the allocation block size is 1 KB, 1000 1 byte files will report a total size of 1 MB, even though 1 KB of data is all that exists. The greater the number of files, the larger this discrepancy may become.

Evaluating Performance Using the All Log Entries Report

  1. Run the backup or restore job.

  2. Run the All Log Entries report from the NetBackup reports node in the NetBackup Administrative Console in release 4.5, or the NetBackup Reports GUI in earlier releases. Be sure that the Date/Time Range that you select covers the time period during which the job was run.

  3. Verify that the job completed successfully by searching for an entry such as 'the requested operation was successfully completed' for a backup, or 'successfully read (restore) backup id ' for a restore.

  4. Obtain the NetBackup performance statistics from the following entries in the report. (Note that the entries shown here are based on release 4.5. The entries for earlier releases will be the same or similar.)

ENTRY

STATISTIC

started backup job for client < name>, policy <name>, schedule <name> on storage unit <name>

The Date and Time fields for this entry show the time at which the backup job started.

successfully wrote backup id <name>, copy <number>, <number> Kbytes

For a multiplexed backup, this entry shows the size of the individual backup job and the Date and Time fields show the time at which the job finished writing to the storage device. The overall statistics for the multiplexed backup group, including the data throughput rate to the storage device, are found in a subsequent entry below.

successfully wrote <number> of <number> multiplexed backups, total Kbytes <number> at Kbytes/sec

For multiplexed backups, this entry shows the overall statistics for the multiplexed backup group including the data throughput rate.

successfully wrote backup id <name>, copy <number>, fragment <number>, <number> Kbytes at <number> Kbytes/sec

For non-multiplexed backups, this entry essentially combines the information in the previous two entries for multiplexed backups into one entry showing the size of the backup job, the data throughput rate, and the time, in the Date and Time fields, at which the job finished writing to the storage device.

the requested operation was successfully completed

The Date and Time fields for this entry show the time at which the backup job completed. This value is later than the 'successfully wrote' entry above because it includes extra processing time at the end of the job for tasks such as NetBackup image validation.

begin reading backup id <name>, (restore), copy <number>, fragment <number> from media id <name> on drive index <number>

The Date and Time fields for this entry show the time at which the restore job started reading from the storage device. (Note that the latter part of the entry is not shown for restores from disk, as it does not apply.)

successfully restored from backup id <name>, copy <number>, <number> Kbytes

For a multiplexed restore (generally speaking, all restores from tape are multiplexed restores as non-multiplexed restores require additional action from the user), this entry shows the size of the individual restore job and the Date and Time fields show the time at which the job finished reading from the storage device. The overall statistics for the multiplexed restore group, including the data throughput rate, are found in a subsequent entry below.

successfully restored <number> of <number> requests <name>, read total of <number> Kbytes at <number> Kbytes/sec

For multiplexed restores, this entry shows the overall statistics for the multiplexed restore group, including the data throughput rate.

successfully read (restore) backup id media <number>, copy <number>, fragment <number>, <number> Kbytes at <number> Kbytes/sec

For non-multiplexed restores (generally speaking, only restores from disk are treated as non-multiplexed restores), this entry essentially combines the information from the previous two entries for multiplexed restores into one entry showing the size of the restore job, the data throughput rate, and the time, in the Date and Time fields, at which the job finished reading from the storage device.

Additional Information

The NetBackup All Log Entries report will also have entries similar to those described above for other NetBackup operations such as image duplication operations used to create additional copies of a backup image. Those entries have a very similar format and may be useful for analyzing the performance of NetBackup for those operations.

The bptm debug log file will contain the entries that are in the All Log Entries report, as well as additional detail about the operation that may be useful for performance analysis. One example of this additional detail is the intermediate data throughput rate message for multiplexed backups, as shown below:

  intermediate after <number> successful, <number> Kbytes at <number>  Kbytes/sec 

This message is generated whenever an individual backup job completes that is part of a multiplexed backup group. In the debug log file for a multiplexed backup group consisting of three individual backup jobs, for example, there could be two intermediate status lines, then the final (overall) throughput rate.

For a backup operation, the bpbkar debug log file will also contain additional detail about the operation that may be useful for performance analysis. One such example would be data regarding the delay involved in initializing OTM to back up open files on the NetBackup client.

Keep in mind, however, that writing the debug log files during the NetBackup operation introduces some overhead that would not normally be present in a production environment. Factor that additional overhead into any calculations done on data captures while debug log files are in use.

See the NetBackup Troubleshooting Guide to learn how to set up NetBackup to write these debug log files during the NetBackup operation.



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Implementing Backup and Recovery(c) The Readiness Guide for the Enterprise
Implementing Backup and Recovery: The Readiness Guide for the Enterprise
ISBN: 0471227145
EAN: 2147483647
Year: 2005
Pages: 176

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