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

restore performance. The results confirm that the I/O infrastructure and tape devices are no longer the

limiting factors for restore operations. With the added overhead of writing to the file system and

storage, restore throughput averages about one-third of the backup performance.

Client server results

While this performance characterization effort focuses mostly on the backup server, valuable

information was collected on the client systems. To recap, eight client systems were used to provide

backup data to a network backup server. Each client system sends four concurrent data streams over

a single 1GbE port at approximately 113 MB/s. The network backup server has eight aggregated

1GbE ports, providing a dedicated network link for each client system’s data. The data streams from

each pair of clients — eight data streams in total per pair of clients — are configured so that they are

written to one LTO-4 tape device for backup. This same backup media is used for the restore

characterization tests, where data for pairs of clients is restored concurrently.

To prevent distortion of the performance results, no other activities or applications were run on the

client systems during the backup and restore operations. The following subsections summarize the

most salient results.

Comparing SAS and SAN connected storage of client data

Another opportunistic objective of this characterization effort was to determine whether locating client

data on directly-attached SAS storage or SAN-fabric-connected storage significantly affects backup

and restore performance. For both backup and restore operations, no performance differences

were perceived. The most interesting finding is that the major performance-limiting factor is the

amount of memory in the client, much more so than the amount of CPU available and the type of

storage interconnect.

Client backup performance statistics

Figure 8 shows client-level backup performance statistics for four different client configurations:

• rx2600, 2 processors, 2 GB memory

• rx2600, 2 processors, 4 GB memory

• rx3600, 2 dual core (4 CPUs), 8 GB memory

• rx6600, 1 dual core (2 CPUs), 4 GB memory