HP StorageWorks 1606 HP StorageWorks Fabric OS 6.3.0 release notes (5697-0358, - Page 34

Port Fencing, ICLs, Extended Fabrics and R_RDY flow control, Implementation

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Port Fencing • For Port Fencing, once the trigger threshold is exceeded (for example, for ITWs, CRCs, or LRs), Fabric Watch waits for approximately six seconds to see if the port is going offline. If it is still online at the next poll cycle, Fabric Watch fences the port. Extensive testing has shown that ports in the process of going offline may exhibit bursts of errors. Waiting the additional six seconds to check the port status helps prevent false positives and unnecessarily fencing a port (for example, during a server reboot). • When using Port Fencing, you must first run the fwalarmsfilterset command. This command enables the port and allows you to receive Port Fencing messages. • The state-changes counter used by Fabric Watch in Fabric OS 6.3 has been updated to ignore any toggling of F_Ports due to planned internal mechanisms, such as throttling and trunking. There are some Fabric OS CLI commands, such as portcfgspeed and portCfgTrunkPort, that implicitly disable/enable ports after configuration. • Fabric Watch monitors state change for LISL ports, even though it is not displayed in Fabric Watch CLI commands. ICLs • If a DC SAN Director with an 8-link ICL license is connected to a DC SAN Director with a 16-link license, the DC SAN Director with the 16-link license will report enc_out errors. The errors are harmless, but will continue to increment. These errors will not be reported if a DC SAN Director with a 16-link license is connected to a DC04 SAN Director with only 8-link ICL ports. • If ICL ports are disabled on only one side of an ICL link, the enabled side may see enc_out errors. Extended Fabrics and R_RDY flow control • Starting with Fabric OS 5.1, the Extended Fabrics feature is supported with R_RDY flow control. (R_RDY flow control mode can be enabled using the portCfgISLMode command.) R_RDY flow control mode that uses IDLE primitives does not support frame-based trunking for devices such as Time Division Multiplexor (TDM). To overcome this limitation and provide support for frame-based trunking with Extended Fabrics, Fabric OS 6.2.x and later has been enhanced to support interoperability with these distance extension devices. Fabric OS 6.3.0 allows Extended Fabrics E_Ports to operate in VC_RDY mode using either ARB or IDLE primitives as fill words. This allows frame-based trunking to be supported on Extended Fabrics E_Ports even when IDLE primitives are configured for these ports when operating in native VC_RDY mode. Prior to this change, frame-based trunking was supported only when ARB primitives were used in VC_RDY mode. With Fabric OS 6.2.x, frame-based trunking is supported on Extended Fabrics E_Ports even if IDLE or ARB primitives are used when operating in native VC_RDY mode. Implementation The portcfglongdistance CLI parameter VC Translation Link Init is now overloaded to specify whether the long-distance link should use IDLE or ARB primitives. By default vc_init is enabled. When vc_init is enabled, the long-distance link uses ARB primitives. When vc_init is disabled, the link uses IDLE primitives. The buffer-to-buffer credit recovery feature is not supported on Extended Fabrics E_Port when it is configured to use IDLE primitives. The user must disable the buffer-to-buffer credit recovery feature using the portcfgcreditrecovery command and specifying the disable option; otherwise, the link will continuously reset. 34

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Port Fencing
•
For Port Fencing, once the trigger threshold is exceeded (for example, for ITWs, CRCs, or LRs),
Fabric Watch waits for approximately six seconds to see if the port is going offline. If it is still
online at the next poll cycle, Fabric Watch fences the port. Extensive testing has shown that ports
in the process of going offline may exhibit bursts of errors. Waiting the additional six seconds to
check the port status helps prevent false positives and unnecessarily fencing a port (for example,
during a server reboot).
•
When using Port Fencing, you must first run the
fwalarmsfilterset
command. This command
enables the port and allows you to receive Port Fencing messages.
•
The state-changes counter used by Fabric Watch in Fabric OS 6.3 has been updated to ignore
any toggling of F_Ports due to planned internal mechanisms, such as throttling and trunking. There
are some Fabric OS CLI commands, such as
portcfgspeed
and
portCfgTrunkPort
, that
implicitly disable/enable ports after configuration.
•
Fabric Watch monitors state change for LISL ports, even though it is not displayed in Fabric Watch
CLI commands.
ICLs
•
If a DC SAN Director with an 8-link ICL license is connected to a DC SAN Director with a 16-link
license, the DC SAN Director with the 16-link license will report
enc_out
errors. The errors are
harmless, but will continue to increment. These errors will not be reported if a DC SAN Director
with a 16-link license is connected to a DC04 SAN Director with only 8-link ICL ports.
•
If ICL ports are disabled on only one side of an ICL link, the enabled side may see
enc_out
errors.
Extended Fabrics and R_RDY flow control
•
Starting with Fabric OS 5.1, the Extended Fabrics feature is supported with R_RDY flow control.
(R_RDY flow control mode can be enabled using the
portCfgISLMode
command.) R_RDY flow
control mode that uses IDLE primitives does not support frame-based trunking for devices such as
Time Division Multiplexor (TDM). To overcome this limitation and provide support for frame-based
trunking with Extended Fabrics, Fabric OS 6.2.x and later has been enhanced to support interop-
erability with these distance extension devices.
Fabric OS 6.3.0 allows Extended Fabrics E_Ports to operate in VC_RDY mode using either ARB
or IDLE primitives as fill words. This allows frame-based trunking to be supported on Extended
Fabrics E_Ports even when IDLE primitives are configured for these ports when operating in native
VC_RDY mode. Prior to this change, frame-based trunking was supported only when ARB primitives
were used in VC_RDY mode. With Fabric OS 6.2.x, frame-based trunking is supported on Extended
Fabrics E_Ports even if IDLE or ARB primitives are used when operating in native VC_RDY mode.
Implementation
The
portcfglongdistance
CLI parameter
VC Translation Link Init
is now overloaded
to specify whether the long-distance link should use IDLE or ARB primitives. By default
vc_init
is
enabled. When
vc_init
is enabled, the long-distance link uses ARB primitives. When
vc_init
is
disabled, the link uses IDLE primitives.
The buffer-to-buffer credit recovery feature is not supported on Extended Fabrics E_Port when it is
configured to use IDLE primitives. The user must disable the buffer-to-buffer credit recovery feature
using the
portcfgcreditrecovery
command and specifying the disable option; otherwise, the
link will continuously reset.
34