HP StoreOnce Backup System Concepts and Configuration Guidelines (BB877-90913, November 2013)

ingest of the StoreOnce appliance is 600MB/sec but we can only achieve 500 MB/sec because
that is as fast we we can supply the data (because of stream limitations). If we could re-configure
the backups to provide more streams, we could get higher throughput.
In example 4 (brown circle) we show a more realistic situation where we have a mixture of different
hosts with different performance levels. Most importantly, we have 30 streams and a total throughput
capability of 950 MB/sec, which puts us very close to the maximum ingest rate. The maximum
ingest rates vary according to each StoreOnce model.
Typically, on the larger StoreOnce units about 48 streams spread across the configured devices
give the best throughput; more streams only help to sustain the throughput with each stream being
throttled appropriately. For example, if 96 streams are configured, the throughput is still the same
as if 48 streams were configured – it is just that each stream runs slower as resources are shared.
Once we understand the basic streams versus performance concept we can start to apply best
practices for the number of devices to configure.
With these factors in mind we have recommended some VTL configurations for the above
performance examples, which are illustrated in the following graph.
Figure 4 Relationship between active data streams and device configuration ( VTLs shown)
Note2 above: In general, per device configured we get the best throughput between 12-16 streams
and the best throughput per appliance when we reach 48 streams or more. So, for 100 streams
20 HP StoreOnce technology