HP Data Protector Software Performance White Paper

46
Local restore of small files
The files were restored directly from the SCSI-attached Ultrium 960 tape drive.
For Windows, test 1 in Table 6 shows that the tape device did not read faster than 156.00 MB/s.
Test 2 shows that the disk device resulted in 19.94 MB/s single write performance. Test 3, with
Data Protector, resulted in just 3.38 MB/s single restore performance. Here, the bottleneck was
the file system which was very busy during the recovery. Millions of small files were written back
with their original names and file attributes. The tape device was always in start/stop mode.
Note: With Windows, test 4 with parallel writes to file systems was not possible due to problems
with an overflow of the Windows system paged pool. See the section Disk write performance
on
page 35. For that reason, HP-UX test 4 was skipped.
For HP-UX, test 2 in Table 6 shows a much better disk write performance (51.41 MB/s) than for
Windows (19.94 MB/s). If you compare the results of test 3 between Windows (3.38 MB/s) and
HP-UX (20.76 MB/s), the difference is even bigger. This shows how efficient the HP-UX file
system is.
Table 6. Local restore of small files – bottleneck determination
Test Performance (MB/s) Bottleneck?
1. Windows L&TT Tape Read
6
156.00 No
2. Windows HPCreateData Single
6
19.94
Yes (File System)
3. Windows DP Ultrium 960 Single 3.38
Yes (File System)
4. Windows DP Ultrium 960 Parallel - -
1. HP-UX L&TT Tape Read
6
160.71 No
2. HP-UX HPCreateData Single
6
51.41
Yes (File System)
3. HP-UX DP Ultrium 960 Single 20.76
Yes (File System)
4. HP-UX DP Ultrium 960 Parallel - -
6
Tested in the section Evaluating tape and disk drive performance on page 32