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

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Test results: implications for optimizing the test environment
The results of the various limits, stress, and tuning tests described previously help define an optimal
configuration for the network backup server test environment.
The backup server configuration includes two 4Gb FC dual-port HBAs (four ports in total) and four HP
LTO-4 tape devices. For maximum throughput in this configuration, the LTO-4 tape devices are
connected so that each tape device has its own dedicated FC port.
Testing shows that the network bandwidth limit for each client system’s 1GbE port is about 113 MB/s.
Although focused testing shows that three concurrent data streams on the client can sustain saturation
of the 1GbE port at 113 MB/s, configuring four parallel data streams on each client accommodates
temporary lags in any individual data stream, ensuring consistent, maximum client data-transfer rates
to the backup server.
Using a backup utility tuning combination of 32 buffers and 256KB I/O block size, along with the
established test data mix, the 113 MB/s maximum throughput capability of a single client’s 1GbE
port factors conveniently in the measured 225 MB/s average sustained backup I/O rate of the HP
LTO-4 tape devices. Thus, with two clients, each having four concurrent data streams, this
configuration can achieve an average total throughput of about 226 MB/s (2 clients * 113 MB/s) of
backup data to a single HP LTO-4 tape device.
Eight clients are required to drive the four LTO-4 tape devices at optimal throughput (each LTO-4 tape
device paired with two clients, each client providing four data streams).
These findings determined the final hardware and software configuration for the test environment
shown in Figure 1. Because each unique backup server environment includes different client systems
and unique network and tape throughput characteristics, similar testing and tuning analyses should be
performed to ensure maximum efficiency.
Analysis of test results for backup servers and client systems
Results of the characterization testing are split into two sections, one section for the backup servers
and the other for the client systems used in the test configuration.
Backup server results
The tests compared the rx3600 and rx6600 Integrity server performing as a backup server. The tests
also compared the backup and restore performance of the rx3600 backup server model.
Comparing rx3600 and rx6600 backup server performance
Figure 6 shows the backup server performance achieved for the rx3600 and rx6600 Integrity servers,
using the Data Protector backup utility and from one-to-four tape devices per server. For each tape
device configuration, the figure shows the total data throughput per server, along with the associated
CPU utilization (CPU %) and memory utilization (MEM %).