How to achieve over 2 TB/hr network backup with Integrity entry-class servers running HP-UX 11i v3

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Figure 6: Data Protector backup server performance comparing rx3600 and rx6600
The rx3600 server configuration has half the processors and memory of the rx6600 configuration.
The chart above shows that the performance scaling of the rx3600 server is eventually limited by the
amount of processing power available. With four LTO-4 tape devices, the rx3600 reaches 99% CPU
utilization while achieving about 500 MB/s total data throughput; in contrast, the rx6600 reaches
about 70% CPU utilization while achieving about 643 MB/s total data throughput.
For both servers, CPU utilization increases with additional tape devices, while memory utilization
remains at about 23%.
Given that the rx6600 server is only at 70% CPU and 23% memory utilization with four LTO-4 tape
devices, additional capacity is available to scale further for servicing a larger client base or hosting
additional mission critical services.
Comparing backup and restore performance – rx3600 backup server
A decade ago, the general rule was that restore operations would take about twice as long as
backup operations. The main reason for this difference is that the restore requires additional time to
allocate storage blocks for the data and for writing that data to disk on the client. Also at that time,
tape devices and the I/O infrastructure were much slower in throughput capability, enabling the file
systems to keep up with the restore data rate for recovery operations.
Today, the I/O infrastructure and devices, especially tape devices, have significantly increased in
speed and capacity (ever more so within the last few years), making backup operations much faster
overall. As a result, I/O infrastructure and tape devices are no longer the limiting factors for a restore
operation. Now the limiting factors tend to be the file system layer and the writing of data to disk.
To compare the restore performance of the tape devices and I/O infrastructure with the performance
of the file system and its associated overhead for allocating files and writing file data to storage, a
series of different restore methods were performed:
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60
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100
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100
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1 Tape
2 Tapes
3 Tapes
4 Tapes
Total Data Throughput (MB/s)
rx6600 (8 CPU / 32
GB mem)
rx3600 (4 CPU / 16
GB mem)
rx6600 CPU%
rx6600 Mem%
rx3600 CPU%
rx3600 Mem%