HP StorageWorks Multi-protocol Router XPath OS 7.4.1d Release Notes (AV-RW5LM-TE, March 2007)
Issue
Description
Meta-SAN traffic In a non-routed SAN, if there are multiple E_Por t links between two switches and
fabric reconfigurations occur due to the loss of a single E_Port link, then traffic
around the fabric is generally not interrupted (or is interrupted for a very short time:
for example, less than one second).
Due to a design decision in this release of the Router, traffic disruption for routed
traffic always occurs for a short period (less than one second), even if EX_Port
links remain available. The manager of a non-routed SAN will not expect this
performance characteristic.
During testing, applications h ave been shown to tolerate the traffic disruption in the
routed fabric and to recover based on an application specific recovery timeline,
which is typically longer than when the fabric again permits traffic to flow. However,
thecommonlyusedI/Otesttool,Iometer,isknowntopanicorcrashundercertain
circumstances of traffic disruption; this has been witnessed to occur in large routed
fabric configurations.
Edge fabri
c switch booting and
EX_Ports
Certain co
nfiguration values and versions of Fabric OS switches in edge fabrics
might caus
e EX_Ports on the Router to be disabled when the switches are rebooted.
EvidenceoftheunexpecteddisabledEX_PortcanbeseenintheRouter’sport
display:
# switchshow
:
7 id AN No_Light disabled EX_PORT
(Last error: Failed to init in time)
Workaround for switches running FOS 3.x /4.x:
• Issue the diagdisablepost command on edge switches
connected to Router EX_Ports.
• Upgrade edge switches to Fabric OS 3.x/4.x.
• Manually enable any disabled EX_Ports when the condition occurs.
Edge fabric segmentation If an edge fabric in which multiple EX_Ports are linked to multiple edge switches
segments into two or more fabrics, all EX_Ports connected to any of the new fabrics
resulting from the segmentation will be disabled due to a fabric ID (FID) conflict error.
If the edge fabric remerges into a single fabric, the EX_Ports that were disabled
remain disabled until administratively enabled. This characteristic is by design, to
prevent erroneous meta-SAN configurations from forming.
Fibre Channel test equipment
Fibre Channel test equipment must use a maximum frame size of 2048 bytes or less
when used with the MP Router.
FibreChannelHBAsarenotaffectedbythisissue,becausemaximumframesize
is typically negotiated during N_Port login (PLOGI).
Table 7 FCIP service
Issue
Description
Serverless backup
applications and
routed fabrics
With routed fabrics, serverless backup using SCSI Extended Copy (XCOPY)
commands is not supported if the backup server and copy manager reside on
different fabrics and the target descriptor(s) in the Extended Copy command
contains port IDs (descriptor type codes E1h or E2h).
FCIP with Continuous
Access EVA, XP,
or HSG80 DRM
(exchange-based
trunking feature)
MP Router Fibre Channel over IP (FCIP) ports utilized for Continuous Access EVA,
XP, or HSG80 D RM must have the exchange-based trunking feature disabled.
Disabling exchange trunking across FCIP port processors can be accomplished
using the following commands :
portCfgFcip -m 2
FCIP portcfgfcip [-m LOAD_BAL (1-exchange, 2-SID_DID,
3-none]
The default is 1. Must be set to 2 or 3 f or Continuous Access EVA, XP, or HSG80
DRM.
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