Something I’ve done recently, the switch has been in for over a year, but was put in, in a hurry, and we’d never got round to finishing off the configuration fully until now.
It has two processor supervisor blades, but its always been running in RPR mode, as we now run VMware ISCSI traffic through it, it being in this mode means a supervisior failure would result in a 2 minute failover before traffic would flow to the secondary supervisor blade. Tollerable (just) for network traffic no so for ISCSI, we’d have some crashed or very sad virtual machines after that.
So I enabled SSO on the switch to get the seamless (near lossless) failover of the supervisors. This way we don’t have to worry about a loss of traffic through the failover, and we don’t get a break in the ISCSI traffic.
There are three modes: Cold, warm and hot of the redundancy.
These relate as:
RPR The show module command displays Cold
RPR+ The show module command displays Warm
SSO The show module command displays Hot
Therefore we want to use SSO as it will give us virtually no downtime RPR+ means about a 30 second gap in traffic, and RPR means about 2 minutes, as we have to wait for the whole supervisor to boot up from scratch.
CITATION:https://supportforums.cisco.com/docs/DOC-4028
#show redundancy
Redundant System Information :
------------------------------
Available system uptime = 14 weeks, 2 days, 6 hours, 27 minutes
Switchovers system experienced = 2
Standby failures = 0
Last switchover reason = active unit failed
Hardware Mode = Duplex
Configured Redundancy Mode = RPR
Operating Redundancy Mode = RPR
Maintenance Mode = Disabled
Communications = Up
Current Processor Information :
-------------------------------
Active Location = slot 5
Current Software state = ACTIVE
Uptime in current state = 4 days, 22 hours, 51 minutes
Image Version = Cisco IOS Software, Catalyst 4500 L3 Switch Software (cat4500e-ENTSERVICESK9-M), Version 12.2(53)SG2, RELEASE SOFTWARE (fc1)
Technical Support: http://www.cisco.com/techsupport
Copyright (c) 1986-2010 by Cisco Systems, Inc.
Compiled Tue 16-Mar-10 04:50 by prod_rel_team
BOOT = bootflash:cat4500e-entservicesk9-mz.122-53.SG2.bin,1;
Configuration register = 0x2102
Peer Processor Information :
----------------------------
Standby Location = slot 6
Current Software state = STANDBY COLD
Uptime in current state = 4 days, 22 hours, 50 minutes
Image Version = Cisco IOS Software, Catalyst 4500 L3 Switch Software (cat4500e-ENTSERVICESK9-M), Version 12.2(53)SG2, RELEASE SOFTWARE (fc1)
Technical Support: http://www.cisco.com/techsupport
Copyright (c) 1986-2010 by Cisco Systems, Inc.
Compiled Tue 16-Mar-10 04:50 by
BOOT = bootflash:cat4500e-entservicesk9-mz.122-53.SG2.bin,1;
Configuration register = 0x2102
Currently we are running in RPR mode, see here the bit of the configuration:
redundancy
mode rpr
main-cpu
auto-sync standard
Now we want to turn on SSO so we do this:
# redundancy
# mode ssoAnswer yes to rebooting the standby, once it has rebooted itself it will come back up in SSO mode.
You can watch it do its thing by starting terminal monitor.
# terminal monitorNow check that it is all up and running, as it is in SSO mode, we should now wee that the software state is: “STANDBY HOT”:
# show redundancyRedundant System Information:
Available system uptime = 14 weeks, 2 days, 6 hours, 36 minutes
Switchovers system experienced = 2
Standby failures = 1
Last switchover reason = active unit failed
Hardware Mode = Duplex
Configured Redundancy Mode = Stateful Switchover
Operating Redundancy Mode = Stateful Switchover
Maintenance Mode = Disabled
Communications = Up
Current Processor Information :
-------------------------------
Active Location = slot 5
Current Software state = ACTIVE
Uptime in current state = 4 days, 23 hours, 0 minutes
Image Version = Cisco IOS Software, Catalyst 4500 L3 Switch Software (cat4500e-ENTSERVICESK9-M), Version 12.2(53)SG2, RELEASE SOFTWARE (fc1)
Technical Support: http://www.cisco.com/techsupport
Copyright (c) 1986-2010 by Cisco Systems, Inc.
Compiled Tue 16-Mar-10 04:50 by prod_rel_team
BOOT = bootflash:cat4500e-entservicesk9-mz.122-53.SG2.bin,1;
Configuration register = 0x2102
Peer Processor Information :
----------------------------
Standby Location = slot 6
Current Software state = STANDBY HOT
Uptime in current state = 2 minutes
Image Version = Cisco IOS Software, Catalyst 4500 L3 Switch Software (cat4500e-ENTSERVICESK9-M), Version 12.2(53)SG2, RELEASE SOFTWARE (fc1)
Technical Support: http://www.cisco.com/techsupport
Copyright (c) 1986-2010 by Cisco Systems, Inc.
Compiled Tue 16-Mar-10 04:50 by
BOOT = bootflash:cat4500e-entservicesk9-mz.122-53.SG2.bin,1;
Configuration register = 0x2102