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This chapter describes the fabric login (FLOGI) database, the name server features, the Fabric-Device Management Interface, and Registered State Change Notification (RSCN) information provided in the Cisco MDS 9000 Family. It includes the following sections:
In a Fibre Channel fabric, each host or disk requires an Fibre Channel ID. Use the show flogi database command to verify if a storage device is displayed in the FLOGI table as in the next section. If the required device is displayed in the FLOGI table, the fabric login is successful. Examine the FLOGI database on a switch that is directly connected to the host HBA and connected ports.
The name server functionality maintains a database containing the attributes for all hosts and storage devices in each VSAN. Name servers allow a database entry to be modified by a device that originally registered the information.
The proxy feature is useful when you want to modify (update or delete) the contents of a database entry that was previously registered by a different device.
This section includes the following topics:
In order to improve the performance of the Fibre Channel protocols on the Cisco MDS 9000 switch, the name server optimizes the remote entry change notifications by sending multiple notifications in one MTS payload. Nearly 10 other components that receive this MTS notification would have to function on the single bulk notification instead of multiple notifications.
For NX-OS Release 6.2(1) to 6.2(7), bulk notification is disabled by default. Enabling this feature in one switch has no bearing on the other switches in the same fabric.
 Note |
From NX-OS Release 6.2(9) onwards, bulk notification is enabled by default. |
Note |
The above restrictions are applicable only to release 6.2.7. |
To enable the name server bulk notification, follow these steps for NX-OS Release 6.2(1) to 6.2(7):
|
Step 1 |
switch# config t Enters configuration mode. |
|
Step 2 |
switch(config)# fcns bulk-notify switch(config)# Enables the transmission of multiple name server entry change notification in one Messaging and Transaction Services (MTS) payload. |
To disable the name server bulk notification, follow these steps for NX-OS Release 6.2(1) to 6.2(7):
|
Step 1 |
switch# config t Enters configuration mode. |
|
Step 2 |
switch(config)# no fcns bulk-notify switch(config)# Disables the transmission of multiple name server entry change notification in one Messaging and Transaction Services (MTS) payload. |
To disable the name server bulk notification, follow these steps for NX-OS Release 6.2(9) and later:
|
Step 1 |
switch# config t Enters configuration mode. |
|
Step 2 |
switch(config)# fcns no-bulk-notify switch(config)# Disables the transmission of multiple name server entry change notification in one Messaging and Transaction Services (MTS) payload. |
To re-enable once it is disabled already for NX-OS Release 6.2(9) and later, follow these steps:
|
Step 1 |
switch# config terminal Enters configuration mode. |
|
Step 2 |
switch(config)# no fcns no-bulk-notify switch(config)# Re-enables the transmission of multiple name server entry change notification in one Messaging and Transaction Services (MTS) payload. |
All name server registration requests are sent from the same port with a parameter that is registered or changed. If the port that does not have the parameter, then the request is rejected.
This authorization enables WWNs to register specific parameters for another node.
To register the name server proxy, follow these steps:
|
Step 1 |
switch# config terminal switch(config)# Enters configuration mode. |
|
Step 2 |
switch(config)# fcns proxy-port 21:00:00:e0:8b:00:26:d0 vsan 2 Configures a proxy port for the specified VSAN. |
By FC standard, NX-OS will accept a login on any interface of a pwwn that is already logged in on the same switch, same vsan and same fcdomain. To prevent the same pwwn from logging in the same switch on a different interface, use the port security feature.
By default, any future flogi (with duplicate pwwn) on different switch in the same vsan, will be rejected and previous FLOGI retained, which does not follow FC standards. If you disable this option, any future flogi (with duplicate pwwn) on different switch in the same VSAN, would be allowed to succeed by deleting previous FCNS entry
To reject duplicate pWWNs, follow these steps:
|
Step 1 |
switch# configure terminal switch(config)# Enters configuration mode. |
|
Step 2 |
switch(config)# fcns reject-duplicate-pwwn vsan 1 Any future flogi (with duplicate pwwn) on different switch, will be rejected and previous FLOGI retained. (default) |
|
Step 3 |
switch(config)# no fcns reject-duplicate-pwwn vsan 1 Any future flogi (with duplicate pwwn) on different switch, will be allowed to succeed by deleting earlier FCNS entry. But you can still see the earlier entry in FLOGI database in the other switch. |
The name server stores name entries for all hosts in the FCNS database. The name server permits an Nx port to register attributes during a PLOGI (to the name server) to obtain attributes of other hosts. These attributes are deregistered when the Nx port logs out either explicitly or implicitly.
In a multiswitch fabric configuration, the name server instances running on each switch shares information in a distributed database. One instance of the name server process runs on each switch.
If an end device doesn't register FC4 feature with Name Server database, VHBA (also called scsi-target) component would perform PRLI to the end device to discover FC4 feature and register with Name Server on behalf of end device. This discovery from VHBA was performed both for locally connected devices
as well as remotely connected devices. This discovery was unnecessary for remotely connected devices because, Name Server would get FC4 feature of remotely connected devices through regular Name Server sync protocol. So, the default behavior of VHBA component has been modified to discover only locally connected devices. To modify this behavior, follow these steps:
|
Step 1 |
switch(config)# scsi-target discovery Enables a switch to discover fc4-feature for remote devices also. But this would not be the default behavior if the users reload or switchover the switch. |
|
Step 2 |
switch(config)# scsi-target discovery local-only Switches back to the default behavior. |
To Verify the number of name server database entries, follow these steps:
|
Step 1 |
switch# show fcns internal info global Displays the number of device entries in the name server database. |
|
Step 2 |
switch# show fcns internal info Displays the number of devices in the name server database at the end of the output. |
Use the show fcns command to display the name server database and statistical information for a specified VSAN or for all VSANs (see Examples Displays the Name Server Database to Displays the Name Server Statistics).
switch# show fcns database
--------------------------------------------------------------------------
FCID TYPE PWWN (VENDOR) FC4-TYPE:FEATURE
--------------------------------------------------------------------------
0x010000 N 50:06:0b:00:00:10:a7:80 scsi-fcp fc-gs
0x010001 N 10:00:00:05:30:00:24:63 (Cisco) ipfc
0x010002 N 50:06:04:82:c3:a0:98:52 (Company 1) scsi-fcp 250
0x010100 N 21:00:00:e0:8b:02:99:36 (Company A) scsi-fcp
0x020000 N 21:00:00:e0:8b:08:4b:20 (Company A)
0x020100 N 10:00:00:05:30:00:24:23 (Cisco) ipfc
0x020200 N 21:01:00:e0:8b:22:99:36 (Company A) scsi-fcp
switch# show fcns database vsan 1
VSAN 1:
--------------------------------------------------------------------------
FCID TYPE PWWN (VENDOR) FC4-TYPE:FEATURE
--------------------------------------------------------------------------
0x030001 N 10:00:00:05:30:00:25:a3 (Cisco) ipfc
0x030101 NL 10:00:00:00:77:99:60:2c (Interphase)
0x030200 N 10:00:00:49:c9:28:c7:01
0xec0001 NL 21:00:00:20:37:a6:be:14 (Seagate) scsi-fcp
Total number of entries = 4
switch# show fcns database detail
------------------------
VSAN:1 FCID:0x030001
------------------------
port-wwn (vendor) :10:00:00:05:30:00:25:a3 (Cisco)
node-wwn :20:00:00:05:30:00:25:9e
class :2,3
node-ip-addr :0.0.0.0
ipa :ff ff ff ff ff ff ff ff
fc4-types:fc4_features:ipfc
symbolic-port-name :
symbolic-node-name :
port-type :N
port-ip-addr :0.0.0.0
fabric-port-wwn :00:00:00:00:00:00:00:00
hard-addr :0x000000
------------------------
VSAN:1 FCID:0xec0200
------------------------
port-wwn (vendor) :10:00:00:5a:c9:28:c7:01
node-wwn :10:00:00:5a:c9:28:c7:01
class :3
node-ip-addr :0.0.0.0
ipa :ff ff ff ff ff ff ff ff
fc4-types:fc4_features:
symbolic-port-name :
symbolic-node-name :
port-type :N
port-ip-addr :0.0.0.0
fabric-port-wwn :22:0a:00:05:30:00:26:1e
hard-addr :0x000000
Total number of entries = 2
switch# show fcns statistics
registration requests received = 27
deregistration requests received = 0
queries received = 57
queries sent = 10
reject responses sent = 14
RSCNs received = 0
RSCNs sent = 0
Cisco MDS 9000 Family switches provide support for the Fabric-Device Management Interface (FDMI) functionality, as described in the FC-GS-4 standard. FDMI enables management of devices such as Fibre Channel host bus adapters (HBAs) through in-band communications. This addition complements the existing Fibre Channel name server and management server functions.
Using the FDMI functionality, the Cisco NX-OS software can extract the following management information about attached HBAs and host operating systems without installing proprietary host agents:
Prior to Cisco MDS NX-OS 9.4(2), the maximum limit was 255 virtual devices per HBA end device.
FromCisco MDS NX-OS 9.4(2), the maximum limit is 32 virtual devices per HBA end device.
Use the show fdmi command to display the FDMI database information.
switch# show fdmi database
Registered HBA List for VSAN 1
10:00:00:00:c9:32:8d:77
21:01:00:e0:8b:2a:f6:54
switch# show fdmi database detail
Registered HBA List for VSAN 1
-------------------------------
HBA-ID: 10:00:00:00:c9:32:8d:77
-------------------------------
Node Name :20:00:00:00:c9:32:8d:77
Manufacturer :Emulex Corporation
Serial Num :0000c9328d77
Model :LP9002
Model Description:Emulex LightPulse LP9002 2 Gigabit PCI Fibre Channel Adapter
Hardware Ver :2002606D
Driver Ver :SLI-2 SW_DATE:Feb 27 2003, v5-2.20a12
ROM Ver :3.11A0
Firmware Ver :3.90A7
OS Name/Ver :Window 2000
CT Payload Len :1300000
Port-id: 10:00:00:00:c9:32:8d:77
-------------------------------
HBA-ID: 21:01:00:e0:8b:2a:f6:54
-------------------------------
Node Name :20:01:00:e0:8b:2a:f6:54
Manufacturer :QLogic Corporation
Serial Num :\74262
Model :QLA2342
Model Description:QLogic QLA2342 PCI Fibre Channel Adapter
Hardware Ver :FC5010409-10
Driver Ver :8.2.3.10 Beta 2 Test 1 DBG (W2K VI)
ROM Ver :1.24
Firmware Ver :03.02.13.
OS Name/Ver :500
CT Payload Len :2040
Port-id: 21:01:00:e0:8b:2a:f6:54
switch# show fdmi database detail
Registered HBA List for VSAN 1
-------------------------------
HBA-ID: 10:00:00:10:9b:e0:ff:0c
-------------------------------
Node Name :20:00:00:10:9b:e0:ff:0c
Manufacturer :Emulex Corporation
Serial Num :FP13662272
Model :LPe36002-M64
Model Description:Emulex LPe36002-M64 2-Port 64Gb Fibre Channel Adapter
Hardware Ver :0000000
Driver Ver :12.6.0.2
ROM Ver :12.8.351.47
Firmware Ver :12.8.351.47
OS Name/Ver :Linux 4.18.0-193.el8.x86_64 #1 SMP Fri Mar 27 14:35:58 UTC 2020
CT Payload Len :245760
Port-id: 10:00:00:10:9b:e0:ff:0c
Supported FC4 types:1 scsi-fcp fc-gs NVMe
Supported Speed :16G 32G 64G
Current Speed :32G
Maximum Frame Size :2048
OS Device Name :/sys/class/scsi_host/host13
Host Name :localhost.localdomain
-------------------------------
HBA-ID: 21:00:00:24:ff:7e:e6:14
-------------------------------
Node Name :20:00:00:24:ff:7e:e6:14
Manufacturer :QLogic Corporation
Serial Num :RFD1604J61197
Model :QLE2742
Model Description:Cisco QLE2742 Dual Port 32Gb FC to PCIe Gen3 x8 Adapter
Hardware Ver :BK3210407-43 02
Driver Ver :10.01.00.63.08.0-k
ROM Ver :3.62
Firmware Ver :8.08.05 (d0d5)
Port-id: 21:00:00:24:ff:7e:e6:14
Supported FC4 types:scsi-fcp
Supported Speed :8G 16G 32G
Current Speed :16G
Maximum Frame Size :2048
OS Device Name :qla2xxx:host9
Host Name :localhost.localdomain
Port-id: 21:04:00:24:ff:7e:e6:14
Supported FC4 types:scsi-fcp
Supported Speed :8G 16G 32G
Current Speed :16G
Maximum Frame Size :2048
OS Device Name :qla2xxx:host15
Host Name :localhost.localdomain
Port-id: 21:05:00:24:ff:7e:e6:14
Supported FC4 types:scsi-fcp
Supported Speed :8G 16G 32G
Current Speed :16G
Maximum Frame Size :2048
OS Device Name :qla2xxx:host16
Host Name :localhost.localdomain
Port-id: 21:06:00:24:ff:7e:e6:14
Supported FC4 types:scsi-fcp
Supported Speed :8G 16G 32G
Current Speed :16G
Maximum Frame Size :2048
OS Device Name :qla2xxx:host17
Host Name :localhost.localdomain
Port-id: 21:07:00:24:ff:7e:e6:14
Supported FC4 types:scsi-fcp
Supported Speed :8G 16G 32G
Current Speed :16G
Maximum Frame Size :2048
OS Device Name :qla2xxx:host18
Host Name :localhost.localdomain
switch# show fdmi database detail vsan 1
Registered HBA List for VSAN 1
-------------------------------
HBA-ID: 10:00:00:00:c9:32:8d:77
-------------------------------
Node Name :20:00:00:10:9b:e0:ff:0c
Manufacturer :Emulex Corporation
Serial Num :FP13662272
Model :LPe36002-M64
Model Description:Emulex LPe36002-M64 2-Port 64Gb Fibre Channel Adapter
Hardware Ver :0000000
Driver Ver :12.6.0.2
ROM Ver :12.8.351.47
Firmware Ver :12.8.351.47
OS Name/Ver :Linux 4.18.0-193.el8.x86_64 #1 SMP Fri Mar 27 14:35:58 UTC 2020
CT Payload Len :245760
Port-id: 10:00:00:10:9b:e0:ff:0c
Supported FC4 types:1 scsi-fcp fc-gs NVMe
Supported Speed :16G 32G 64G
Current Speed :32G
Maximum Frame Size :2048
OS Device Name :/sys/class/scsi_host/host13
Host Name :localhost.localdomain
Port-id: 10:00:00:00:c9:32:8d:77
-------------------------------
HBA-ID: 21:01:00:e0:8b:2a:f6:54
-------------------------------
Node Name :20:00:00:24:ff:7e:e6:14
Manufacturer :QLogic Corporation
Serial Num :RFD1604J61197
Model :QLE2742
Model Description:Cisco QLE2742 Dual Port 32Gb FC to PCIe Gen3 x8 Adapter
Hardware Ver :BK3210407-43 02
Driver Ver :10.01.00.63.08.0-k
ROM Ver :3.62
Firmware Ver :8.08.05 (d0d5)
Port-id: 21:01:00:e0:8b:2a:f6:54
switch# show fdmi database detail hba-id 21:01:00:e0:8b:2a:f6:54 vsan 1
Node Name :20:01:00:e0:8b:2a:f6:54
Manufacturer :QLogic Corporation
Serial Num :\74262
Model :QLA2342
Model Description:QLogic QLA2342 PCI Fibre Channel Adapter
Hardware Ver :FC5010409-10
Driver Ver :8.2.3.10 Beta 2 Test 1 DBG (W2K VI)
ROM Ver :1.24
Firmware Ver :03.02.13.
OS Name/Ver :500
CT Payload Len :2040
Port-id: 21:01:00:e0:8b:2a:f6:54
The Registered State Change Notification (RSCN) is a Fibre Channel service that informs hosts about changes in the fabric. Hosts can receive this information by registering with the fabric controller (through SCR). These notifications provide a timely indication of one or more of the following events:
This section includes the following topics:
Apart from sending these events to registered hosts, a switch RSCN (SW-RSCN) is sent to all reachable switches in the fabric.
Note |
The switch sends an RSCN to notify registered nodes that a change has occurred. It is up to the nodes to query the name server again to obtain the new information. The details of the changed information are not delivered by the switch in the RSCN sent to the nodes. |
Use the show rscn command to display RSCN information (see Examples Displays Register Device Information and Displays RSCN Counter Information).
switch# show rscn scr-table vsan 1
SCR table for VSAN: 1
---------------------------------------------
FC-ID REGISTERED FOR
---------------------------------------------
0x1b0300 fabric detected rscns
Total number of entries = 1
Note |
The SCR table is not configurable. It is populated when hosts send SCR frames with RSCN information. If hosts do not receive RSCN information, then the show rscn scr-table command will not return entries. |
switch(config)# show rscn statistics vsan 106
Statistics for VSAN: 106
-------------------------
Number of SCR received = 0
Number of SCR ACC sent = 0
Number of SCR RJT sent = 0
Number of RSCN received = 0
Number of RSCN sent = 0
Number of RSCN ACC received = 0
Number of RSCN ACC sent = 0
Number of RSCN RJT received = 0
Number of RSCN RJT sent = 0
Number of SW-RSCN received = 0
Number of SW-RSCN sent = 0
Number of SW-RSCN ACC received = 0
Number of SW-RSCN ACC sent = 0
Number of SW-RSCN RJT received = 0
Number of SW-RSCN RJT sent = 0
Number of CSWR received = 3137
Number of CSWR sent = 0
Number of CSWR ACC received = 0
Number of CSWR ACC sent = 3137
Number of CSWR RJT received = 0
Number of CSWR RJT sent = 0
Number of CSWR RJT not sent = 0If the RSCN multi-pid option is enabled, then RSCNs generated to the registered Nx ports may contain more than one affected port IDs. In this case, zoning rules are applied before putting the multiple affected port IDs together in a single RSCN. By enabling this option, you can reduce the number of RSCNs. For example: Suppose you have two disks (D1, D2) and a host (H) connected to switch 1. Host H is registered to receive RSCNs. D1, D2 and H belong to the same zone. If disks D1 and D2 are online at the same time, then one of the following applies:
Note |
Some Nx ports may not understand multi-pid RSCN payloads. If not, disable the RSCN multi-pid option. |
To configure the multi-pid option, follow these steps:
|
Step 1 |
switch# config terminal switch(config)# Enters configuration mode. |
|
Step 2 |
switch(config)# rscn multi-pid vsan 105 Sends RSCNs in a multi-pid format for VSAN 105. |
A domain format SW-RSCN is sent whenever the local switch name or the local switch management IP address changes. This SW-RSCN is sent to all other domains and switches over the ISLs. The remote switches can issue GMAL and GIELN commands to the switch that initiated the domain format SW-RSCN to determine what changed. Domain format SW-RSCNs can cause problems with some non-Cisco MDS switches (refer to the ).
To suppress the transmission of these SW RSCNs over an ISL, follow these steps:
|
Step 1 |
switch# config terminal switch(config)# Enters configuration mode. |
||
|
Step 2 |
switch(config)# rscn suppress domain-swrscn vsan 105 Suppresses transmission of domain format SW-RSCNs for VSAN 105.
|
In order to improve the performance of the Fibre Channel protocols on the Cisco MDS 9000 switch, SW-RSCNs are delayed, collected and sent as a single coalesced SW-RSCN to all the switches in the fabric in a single Fibre Channel exchange.
Restrictions
To enable the coalesced SW-RSCNs, follow these step:
|
Step 1 |
switch# config terminal Enters configuration mode. |
||
|
Step 2 |
switch(config)# rscn coalesce swrscn vsan 1 switch(config)# Enables coalescing of Switch Registered State Change Notification (SWRSCN) in VSAN 1. The default delay is 500 milliseconds. |
||
|
Step 3 |
switch(config)# rscn coalesce swrscn vsan 1 delay 800 switch(config)# Enables coalescing of Switch Registered State Change Notification (SWRSCN) in VSAN 1. Delays the SW-RSCNs maximum by 800 milliseconds.
|
To disable the coalesced SW-RSCNs, follow these steps:
|
Step 1 |
switch# config terminal Enters configuration mode. |
|
Step 2 |
switch(config)# no rscn coalesce swrscn vsan 1 switch(config)# Disables coalescing of Switch Registered State Change Notification (SWRSCN) in VSAN 1. |
You can clear the counters and later view the counters for a different set of events. For example, you can keep track of how many RSCNs or SW-RSCNs are generated on a particular event (such as ONLINE or OFFLINE events). You can use these statistics to monitor responses for each event in the VSAN.
Use the clear rscn statistics command to clear the RSCN statistics for the specified VSAN.
switch# clear rscn statistics vsan 1
After clearing the RSCN statistics, you can view the cleared counters by issuing the show rscn command.
switch# show rscn statistics vsan 1
Statistics for VSAN: 1
-------------------------
Number of SCR received = 0
Number of SCR ACC sent = 0
Number of SCR RJT sent = 0
Number of RSCN received = 0
Number of RSCN sent = 0
Number of RSCN ACC received = 0
Number of RSCN ACC sent = 0
Number of RSCN RJT received = 0
Number of RSCN RJT sent = 0
Number of SW-RSCN received = 0
Number of SW-RSCN sent = 0
Number of SW-RSCN ACC received = 0
Number of SW-RSCN ACC sent = 0
Number of SW-RSCN RJT received = 0
Number of SW-RSCN RJT sent = 0
Number of CSWR received = 0
Number of CSWR sent = 0
Number of CSWR ACC received = 0
Number of CSWR ACC sent = 0
Number of CSWR RJT received = 0
Number of CSWR RJT sent = 0
Number of CSWR RJT not sent = 0
Because the timeout value for each switch is configured manually, a misconfiguration occurs when different switches time out at different times. This means different N ports in a network can receive RSCNs at different times. Cisco Fabric Services (CFS) alleviates this situation by automatically distributing configuration information to all switches in a fabric. This also reduces the number of SW-RSCNs.
RSCN supports two modes, distributed and nondistributed. In distributed mode, RSCN uses CFS to distribute configuration to all switches in the fabric. In nondistributed mode, only the configuration commands on the local switch are affected.
Note |
All configuration commands are not distributed. Only the rscn event-tov tov vsan vsan command is distributed. |
The RSCN timer is registered with CFS during initialization and switchover. For high availability, if the RSCN timer distribution crashes and restarts or a switchover occurs, it resumes normal functionality from the state prior to the crash or switchover.
Note |
Before performing a downgrade, make sure that you revert the RCSN timer value in your network to the default value. Failure to do so will disable the links across your VSANs and other devices. |
Compatibility across various Cisco MDS NX-OS releases during an upgrade or downgrade is supported by conf-check provided by CFS. If you attempt to downgrade from Cisco MDS SAN-OS Release 3.0, you are prompted with a conf-check warning. You are required to disable RSCN timer distribution support before you downgrade.
By default, the RSCN timer distribution capability is disabled and is therefore compatible when upgrading from any Cisco MDS SAN-OS release earlier than Release 3.0.
RSCN maintains a per-VSAN event list queue, where the RSCN events are queued as they are generated. When the first RSCN event is queued, a per VSAN timer starts. Upon time-out, all the events are dequeued and coalesced RSCNs are sent to registered users. The default timer values minimize the number of coalesced RSCNs sent to registered users. Some deployments require smaller event timer values to track changes in the fabric.
Note |
The RSCN timer value must be the same on all switches in the VSAN. See the RSCN Timer Configuration Distribution. |
Note |
Before performing a downgrade, make sure that you revert the RCSN timer value in your network to the default value. Failure to do so will disable the links across your VSANs and other devices. |
To configure the RSCN timer, follow these steps:
|
Step 1 |
switch# config t switch(config)# Enters configuration mode. |
|
Step 2 |
switch(config)# rscn distribute Enables RSCN timer configuration distribution. |
|
Step 3 |
switch(config)# rscn event-tov 300 vsan 10 Sets the event time-out value in milliseconds for the selected VSAN. In this example, the event time-out value is set to 300 milliseconds for VSAN 12. The range is 0 to 2000 milliseconds. Setting a zero (0) value disables the timer. |
|
Step 4 |
switch(config)# no rscn event-tov 300 vsan 10 Reverts to the default value (2000 milliseconds for Fibre Channel VSANs or 1000 milliseconds for FICON VSANs). |
|
Step 5 |
switch(config)# rscn commit vsan 10 Commits the RSCN timer configuration to be distributed to the switches in VSAN 10. |
You verify the RSCN timer configuration using the show rscn event-tov vsan command.
switch# show rscn event-tov vsan 10
Event TOV : 1000 ms
Because the timeout value for each switch is configured manually, a misconfiguration occurs when different switches time out at different times. This means different N-ports in a network can receive RSCNs at different times. Cisco Fabric Services (CFS) infrastructure alleviates this situation by automatically distributing the RSCN timer configuration information to all switches in a fabric. This also reduces the number of SW-RSCNs. Refer to the Cisco MDS 9000 Family NX-OS System Management Configuration Guide .
RSCN supports two modes, distributed and nondistributed. In distributed mode, RSCN uses CFS to distribute configuration to all switches in the fabric. In nondistributed mode, only the configuration commands on the local switch are affected.
Note |
All configuration commands are not distributed. Only the rscn event-tov tov vsan vsan command is distributed. |
Note |
Only the RSCN timer configuration is distributed. |
The RSCN timer is registered with CFS during initialization and switchover. For high availability, if the RSCN timer distribution crashes and restarts or a switchover occurs, it resumes normal functionality from the state prior to the crash or switchover.
Note |
You can determine the compatibility when downgrading to an earlier Cisco MDS NX-OS release using show incompatibility system command. You must disable RSCN timer distribution support before downgrading to an earlier release. |
Note |
By default, the RSCN timer distribution capability is disabled and is compatible when upgrading from any Cisco MDS SAN-OS release earlier than 3.0. |
Note |
For CFS distribution to operate correctly for the RSCN timer configuration, all switches in the fabric must be running Cisco SAN-OS Release 3.0(1) or later, or Cisco NX-OS 4.1(1b). |
This section includes the following topics:
To enable RSCN timer configuration distribution, follow these steps:
|
Step 1 |
switch# config terminal switch(config)# Enters configuration mode. |
|
Step 2 |
switch(config)# rscn distribute Enables RSCN timer distribution. |
|
Step 3 |
switch(config)# no rscn distribute Disables (default) RSCN timer distribution. |
The first action that modifies the database creates the pending database and locks the feature in the VSAN. Once you lock the fabric, the following situations apply:
If you commit the changes made to the active database, the configuration is committed to all the switches in the fabric. On a successful commit, the configuration change is applied throughout the fabric and the lock is released.
To commit RSCN timer configuration changes, follow these steps:
|
Step 1 |
switch# config t switch(config)# Enters configuration mode. |
|
Step 2 |
switch(config)# rscn commit vsan 10 Commits the RSCN timer changes. |
If you discard (terminate) the changes made to the pending database, the configuration database remains unaffected and the lock is released.
To discard RSCN timer configuration changes, follow these steps:
|
Step 1 |
switch# config t switch(config)# Enters configuration mode. |
|
Step 2 |
switch(config)# rscn abort vsan 10 Discards the RSCN timer changes and clears the pending configuration database. |
If you have changed the RSCN timer configuration and have forgotten to release the lock by either committing or discarding the changes, an administrator can release the lock from any switch in the fabric. If the administrator performs this task, your changes to the pending database are discarded and the fabric lock is released.
 Tip |
The pending database is only available in the volatile directory and are subject to being discarded if the switch is restarted. |
To use administrative privileges and release a locked DPVM session, use the clear rscn session vsan command in EXEC mode.
switch# clear rscn session vsan 10
Use the show cfs application name rscn command to display the registration status for RSCN configuration distribution.
switch# show cfs application name rscn
Enabled : Yes
Timeout : 5s
Merge Capable : Yes
Scope : Logical
Use the show rscn session status vsan command to display session status information for RSCN configuration distribution.
Note |
A merge failure results when the RSCN timer values are different on the merging fabrics. |
switch# show rscn session status vsan 1
Session Parameters for VSAN: 1
-------------------------------
Last Action : Commit
Last Action Result : Success
Last Action Failure Reason : None
Use the show rscn pending command to display the set of configuration commands that would take effect when you commit the configuration.
Note |
The pending database includes both existing and modified configuration. |
switch# show rscn pending
rscn event-tov 2000 ms vsan 1
rscn event-tov 2000 ms vsan 2
rscn event-tov 300 ms vsan 10
Use the show rscn pending-diff command to display the difference between pending and active configurations. The following example shows the time-out value for VSAN 10 was changed from 2000 milliseconds (default) to 300 milliseconds.
switch# show rscn pending-diff
- rscn event-tov 2000 ms vsan 10
+ rscn event-tov 300 ms vsan 10
Table 1 lists the default settings for RSCN.
|
Parameters |
Default |
|---|---|
|
RSCN timer value |
2000 milliseconds for Fibre Channel VSANs1000 milliseconds for FICON VSANs |
|
RSCN timer configuration distribution |
Disabled |
For detailed information, refer to the Cisco MDS 9000 Family NX-OS System Management .
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