Open Systems Tape Pipelining; Fcip Fastwrite And Ostp Configurations - Brocade Communications Systems 8 Administrator's Manual

Open Systems Tape Pipelining

Open Systems Tape Pipelining (OSTP) can be used to enhance open systems SCSI tape write I/O
performance. When the FCIP link is the slowest part of the network, OSTP can provide accelerated
speeds for tape read and write I/O over FCIP tunnels. To use OSTP, you need to enable both FCIP
Fastwrite and Tape Pipelining.
OSTP accelerates SCSI read and write I/Os to sequential devices (such as tape drives) over FCIP,
which reduces the number of round-trip times needed to complete the I/O over the IP network and
speeds up the process. Each GbE port supports up to 2048 simultaneous accelerated exchanges.
Both sides of an FCIP tunnel must have matching configurations for these features to work. FCIP
Fastwrite and OSTP are enabled by turning them on during the tunnel configuration process. They
are enabled on a per-FCIP tunnel basis.

FCIP Fastwrite and OSTP configurations

The FCP features used in FCIP fastwrite and OSTP require a deterministic FC Frame path between
initiators and targets when multiple tunnels exist. If there are non-controlled parallel (equal cost)
tunnels between the same SID/DID pairs, protocol optimization will fail when a command is routed
over one tunnel and the response is returned over a different tunnel. To help understand the
supported configurations, consider the configurations shown in
cases, there are no multiple equal-cost paths. In
and OSTP enabled. In
equal-cost path.
FIGURE 8
Fabric OS FCIP Administrator's Guide
53-1001766-01
Figure 9, there are multiple tunnels, but none of them create a multiple
Single tunnel, Fastwrite and OSTP enabled
Open Systems Tape Pipelining
Figure 8
Figure 8, there is a single tunnel with Fastwrite
Connection can be
VE-VE or VEX-VE
2
and Figure 9. In both
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