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ISSU upgrade on VSS -- standby in bootloop

Level 1
Level 1

Hi all, I have been trying to run updates on our 6506 VSS using the ISSU method.  Everything went smoothly until running the issu loadversion command to boot the standby chassis to the new version.  Now the standby is stuck in a bootloop, each time with the following errors:


*Feb 19 23:20:15.074: %PFREDUN-SW1_SP-4-PHYSMEM_MISMATCH: Asymmetrical redundant configuration: Active SP has (1048576/65536K) memory, Standby has (1048576/8192K).

*Feb 19 23:05:06.844: %ISSU-SW1_SP-3-FSM_MISMATCH_MTU: ISSU nego failed for client ISSU ifs client(110) entity_id 113 session 328042 due to mismatch of mtu size 36 & 72.-Traceback= 40975A1C 41800974 418009E0 40972E30 40973090 40973488 409B57B0 40431C40 40449AD4 40895A0C 408959F8
*Feb 19 23:05:06.880: %ISSU-SW1_SP-4-FSM_INCOMP: Version of local ISSU client ISSU ifs client(110) in session 328042 is incompatible with re
mote side.
*Feb 19 23:05:06.880: %RFS-SW1_SP-3-START_NEGO_SESSION: RFS nego (328042:459040) to [issu:rfs:Secondary RFS Server Port:0x4050000]  failed: [ISSU_RC_NEGO_ERROR]
*Feb 19 23:05:37.691: %RF-SW1_SP-5-RF_RELOAD: Peer reload. Reason: RF Client RFS RF(520) notification timeout


*Feb 19 23:13:16.756: %ISSU-SW2_SPSTBY-4-FSM_INCOMP: Version of local ISSU client ISSU ifs client(110) in session 65692 is incompatible with
remote side.
*Feb 19 23:13:16.756: %RFS-SW2_SPSTBY-3-START_NEGO_SESSION: RFS nego (65692:65691) to [issu:rfs:65536:0x10000] failed: [ISSU_RC_NEGO_ERROR]
*Feb 19 23:13:48.653: %SYS-SW2_SPSTBY-5-RELOAD: Reload requested - From Active Switch (Reload peer unit).

The only way to get out of the bootloop is to wait for the rollback timer to kick in (hopefully, haven't waited that long yet) or manually reset the chassis.

As far as I know, the hardware of both chassis are identical.

We are trying to update from s72033-adventerprisek9_wan-mz.122-33.SXI3.bin to the modular variant of the same IOS version.

Any ideas as to what's going wrong?


2 Replies 2

Reza Sharifi
Hall of Fame
Hall of Fame


It is complaining about incomparable versions. So right now the stand-by has a modular version and the active none-modular? Is the stand-by is passing traffic.? what does "sh swi vir role" shows?

you may have to go back to the original code and then load the new code on both switches and reboot them.  This of course must be done during on outage window.



Same thing happened to me.  I upgraded my VSS using ISSU eSFU with 12.2(33)SXI4 to 4a and encountered the same messages.  As soon as issu loadversion was issued, the script kicked in and attempted to reload the standby.  Except the standby never comes up and boots into Rommon mode.  Then the Peer goes into Disabled state.  I attempted to reboot the standby using various images but it always booted back into Rommon.  This happened so many times that we began to suspect that the ISSU script had corrupted the sup and we had to RMA it.  I should mention that my VSS is fully populated with service modules and was running modular SXI4.

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