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

Figure 3 Relationship between active data streams and device configuration ( VTLs shown)
Note 1: Stream source data rates will vary; some streams will be at 8, others at 50, and maybe
some others at 200. This means that as the stream count increases, it will be the aggregate total
of the streams that will drive the unit to saturation, which is the goal. Some of the factors that
influence source data rate are the compressiblity of data, number of disks in the disk group that
is feeding the stream, RAID type and others.
Note 2: With 5 streams at 100MB/Sec we do not reach the maximum throughput of the node
(server), which can support 600MB/sec in this example. This is the maximum possible ingest rate
of the device for a specific model based on 5 streams. This ingest rate is the maximum even if
each stream is capable of 200MB/Sec, because it represents the maximum amount of data the
machine can process.
Note 3: The number of streams available varies throughout the backup window. The curve
representing backup streams increases as the backup jobs begin ramping into the appliance (to
VTL, NAS share or Catalyst store target devices) and then declines towards the finish of the backup,
when throughput rates decline as backup jobs complete. This highlights the importance of
maintaining enough backup threads from sources to ensure that, while backups are running,
sufficient source “data pump” is maintained to hold the StoreOnce device in saturation.
Notes for the color-coded circles:
In example 1 (red circle) we are supplying much more than 24 streams (100 actually) but they are
all slow hosts and the cumulative ingest rate is 800 MB/sec (below our maximum ingest rate).
In example 2 (green circle) we have some high performance hosts that can supply data at a rate
higher than the StoreOnce maximum ingest rate; and so the performance is capped at 1000
MB/sec.
In example 3 (blue circle) we have some very high performance hosts but can only configure 5
backup streams because of the way the data is constructed on the hosts. In this case the maximum
Backup Application considerations 19