Port Assignment For Storeonce Backup Systems; Zoning - HP StoreOnce 4900 Backup Installation And Configuration Manual

Port assignment for StoreOnce Backup systems

There are two FC cards and, therefore, four FC ports. When creating a library you may select
individual drives or FC ports 1&2 or FC ports 3&4. Be aware that Port 1 and port 3 are on the
first FC card; port 2 and port 4 are on the second FC card, so it is important to verify that the
system is cabled correctly when connecting to the FC SAN. If you select one of the combined port
options, both FC cards must be connected.
Drives can only appear on one port, so when you choose a pair of ports, drives are automatically
distributed evenly across both ports to ensure best performance and failover. After creating the
library, it is possible to change the drive assignments using the edit function on the Interface
Information tab for the selected library. See the HP StoreOnce Backup system user guide for more
details..
If you choose to present the VTL to FC Ports 1 &2 or FC Ports 3&4, the following happens. For this
example, Ports 1&2 are selected.
The robot is presented to both Port1 and Port2.
50% of the configured drives are presented to Port1 and the other 50% to Port2 (this can be
changed if required using the edit function on the Interface Information tab for the selected
library. See the HP StoreOnce Backup system user guide for more information.).
With this configuration in the event of a Fabric Failure – the robot and 50% of the drives are
available for backup.
The disadvantage of this feature is that only a single 8Gb FC link is available for backups to
that library.

Zoning

Zoning is only required if a switched fabric topology is used.
Due to complexities in multi-hosting tape devices on SANs, it is best to make use of zoning tools
to help keep the backup/restore environment simple and less susceptible to the effects of changing
or problematic SANs.
Zoning provides a way for servers, disk arrays, and tape libraries to only see what hosts and
targets they need to see and use. The benefits of zoning include but are not limited to:
Limiting unnecessary discoveries on the HP StoreOnce Backup system.
Reducing stress on the HP StoreOnce Backup system and its library devices by polling agents.
Reducing the time it takes to debug and resolve anomalies in the backup/restore environment.
Reducing the potential for conflict with untested third-party products.
Zoning may not be necessary for small or simple configurations. Typically the bigger the SAN is,
the more zoning is needed. HP recommends the following for determining how and when to use
zoning.
Small fabric (16 ports or less)—may not need zoning.
Small to medium fabric (16 - 128 ports)—use host-centric zoning. Host-centric zoning is
implemented by creating a specific zone for each server or host, and adding only those storage
elements to be used by that host. Host-centric zoning prevents a server from detecting any
other devices on the SAN or including other servers, and it simplifies the device discovery
process.
Disk and tape on the same pair of HBAs is supported along with the coexistence of array
multipath software (no multipath to tape or library devices on the HP StoreOnce Backup system,
but coexistence of the multipath software and tape devices).
Large fabric (128 ports or more)—use host-centric zoning and split disk and tape targets.
Splitting disk and tape targets into separate zones prevents the HP StoreOnce Backup system
Zoning 81