Control Blocks Created During Fcp Traffic Flow; Determining How A Configuration Affects Fcip Tunnel Control; Block Memory - Brocade Communications Systems StoreFabric SN6500B Administrator's Manual

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Memory use limitations for large-device tunnel configurations

Control blocks created during FCP traffic flow

For FICON traffic flows, FCIP tunnel processing creates control block structures based upon the
SID/DID pairs called a FICON device port, path block (FDPB). If any FICON emulation feature is
enabled, additional control blocks are created for each SID/DID pair, LPAR number (FCHB
structure), LCU Number (FCUB structure) and for each individual FICON device address on those
LCUs (FDCB structure).

Determining how a configuration affects FCIP tunnel control

block memory

The portshow xtun <slot/>vePort -fcp -port -stats command displays current usage and control
block sizes per tunnel once control blocks have been allocated. Use output from this command to
determine the unique characteristics for a specific tunnel configuration. The highlighted text in the
following example shows statistics for the control block structures created for FCP and FICON traffic
flows during FCIP tunnel processing.
portshow xtun 1/12 -fcp -port -stats
Slot(1) VePort(12) Port Stats: OK
Global Queue Stats:
Port Queue Stats:
Port Struct Allocation Stats:
Global Buffer Stats:
Use output from portshow xtun <slot/>vePort -fcp -port -stats command in conjunction with output
from the portshow xtun <slot/>vePort -dram2 command to determine how a tunnel configuration is
affecting FCIP tunnel control block memory. As a rule of thumb, no more than 80 percent of the
FCIP tunnel DP complex control block memory pool (dram2) should be allocated for SID/DID pair
related control blocks (ITNs, ITLs, FDPBs, FCHBs, FCUBs and FDCBs). When more than 80 percent
of the pool is allocated, the FCIP tunnel configuration should be re-designed to insure continuous
operation. This design should include examining the existing number of SID/DID pairs in the
configuration and whether or not new switches, chassis, or blades should be acquired to reduce
the percentage of current usage of the dram2.
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Name,cnt,max,usage,size,total size
Data,12,14,44,8192,98304
Message,0,1,9,1432,0
Stat,40,40,80,928,37120
Stat Cache,0,40,40,0,0
Global stats,0,0,0,0,153240
Name,cnt,max,usage,size,total size
Image,40,40,80,0,0
SRB,0,0,0,0,0
TWB,1,40,356,0,0
Name,cnt,max,usage,size
IMAGE,40,40,80,3560
ITN,26,0,0,2984
ITL,1103,0,0,2312
FDPB,30,0,0,3864
FCHB,108,0,0,1400
FCUB,1721,0,0,1592
FDCB,14738,0,0,920
Name,current,min,max
Write Data Storage,0,0,0
Read Data Storage,0,0,0
XBAR % avail,98,98,100
WIRE % avail,95,95,100
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Fabric OS FCIP Administrator's Guide
53-1002748-01