HP D2D Manual page 21

Block size: The Data Path Properties tab also has an option for block size. Leave this at the
default which means it is set as appropriate for the media type.
Use media type setting fixes the block size at 64K.
Use specific value should take into account other considerations, see the information about
VTL emulations in Performance Tunables for Media Management in CommVault Simpana
9.0 Books Online.
In general NAS share performance is much less affected by block size (unlike physical tape
performance which is affected by block size).
4. Select the Data Path Configuration tab. By default, there are no alternative data paths created
and we use the preferred data path. We do not use the round-robin between data paths which
load balances backups across available disk libraries. These settings are important because
we do not want to exceed the open files limits on the D2D NAS share (see later section).
If additional Storage Policies are required use the Storage Policy creation wizard by right clicking
Storage Policies in the main left-hand menu tree.
Storage policy 21