HP Data Protector Software Performance White Paper

Local backup of typical files

The typical files were saved to the SCSI-attached Ultrium 960 tape drive.

For Windows, test 1 in Table 1 shows that that the tape device wrote at 154.00 MB/s. This was

sufficient for backing up a single file system as shown in test 2 with 105.25 MB/s. But when

backing up multiple file systems, as shown in test 3, the file systems were able to provide

262.24 MB/s, which was faster than the Ultrium 960 tape drive. Test 5 showed that the Data

Protector performance of 151.69 MB/s was very close the to the tape drive performance of test

1 with 154.00 MB/s. In test 5, the tape drive was able to stream with its highest performance and

therefore it became the bottleneck. This is a very good example of a well-balanced environment

for an Ultrium 960 tape drive.

For HP-UX, test 1 in Table 1 shows that the results were much better than for Windows but that

the same rules applied. The Ultrium 960 tape drive was the bottleneck.

The CPU load was low except during the HP-UX NULL device backup of test 4, which resulted

in 43% and the excellent backup performance of 368.76 MB/s. Test 5, with the backup to the

Ultrium 960 tape drive, did not stretch the CPU resources. The CPU load was only 13% for

Windows and 16% for HP-UX.

Table 1. Local backup of typical files – bottleneck determination

Test Performance (MB/s) CPU Load Bottleneck?

1. Windows L&TT Tape Write

154 -

Yes (Tape)

2. Windows HPReadData Single

105 - No

3. Windows HPReadData Parallel

262 - No

4. Windows DP NULL Parallel 197 18% No

5. Windows DP Ultrium 960 Parallel 152 13% No

1. HP-UX L&TT Tape Write

159 -

Yes (Tape)

2. HP-UX HPReadData Single

131 - No

3. HP-UX HPReadData Parallel

266 - No

4. HP-UX DP NULL Parallel 3696 43% No

5. HP-UX DP Ultrium 960 Parallel 156 16% No

Recommendation: When backing up typical files locally to the SCSI-attached Ultrium 960 tape

drive, parallel backups (multiplexing/concurrency) are recommended because one single stream

cannot fully use the tape drive.

Tested in the section Evaluating tape and disk drive performance on page 32