Advanced Backup to Disk Performance White Paper

HPReadData
The HPReadData PAT utility is useful in assessing the rate at which your disk subsystem can supply
data, and this is ultimately what will limit the backup performance. It simulates the way DP read files.
A single instance of HPReadData can read eight streams simultaneously from your array. To read
more than eight streams, initiate multiple instances of HPReadData. HPReadData is available for
Windows, HP-UX, Solaris, and Linux. It can be downloaded free from
http://www.hp.com/support/pat.
The performance tools are also embedded within the HP industry-leading Library and Tape Tools
diagnostics which are downloadable from
http://www.hp.com/support/tapetools.
Figure 7. HPReadData for Determination of Read Performance
The above screenshot shows HPReadData reading one single LUN in a manner similar to the way a
backup application will read files. We can see that the maximum read rate from this configuration is
57 MB/s, so we cannot expect any higher back-up transfer performance to tape than this figure.
14