Hi dinistic,

Which model switch is it? Is the stack still working properly?

What does the show redundancy, show system stack-unit and show system brief commands show?

model is DELL S3124F, and the units are still forwarding packets.. the stack is working fine and there is no messages on the terminal monitor when this happens.

this is happening in two stacks (both with 2x S3124F units) in different parts of the campus

I'll send you the commands next monday, when I'm back in the lab.
Thank you

please find the following commands output
show redundancy
show system stack-unit
show system brief commands

DELL-SWITCH#

DELL-SWITCH#show redundancy

-- Stack-unit Status --
------------------------------------------------
Mgmt ID: 1
Stack-unit ID: 1
Stack-unit Redundancy Role: Primary
Stack-unit State: Active
Stack-unit SW Version: 9.14(2.2)
Link to Peer: Up

-- PEER Stack-unit Status --
------------------------------------------------
Stack-unit State: Standby
Peer Stack-unit ID: 2
Stack-unit SW Version: 9.14(2.2)

-- Stack-unit Redundancy Configuration --
------------------------------------------------
Primary Stack-unit: mgmt-id 1
Auto Data Sync: Full
Failover Type: Hot Failover
Auto reboot Stack-unit: Enabled
Auto failover limit: 3 times in 60 minutes

-- Stack-unit Failover Record --
------------------------------------------------
Failover Count: 0
Last failover timestamp: None
Last failover Reason: None
Last failover type: None

-- Last Data Block Sync Record: --
------------------------------------------------
stack-unit Config: succeeded Sep 24 2020 14:04:16
SSMGR: succeeded Sep 24 2020 14:04:16
Start-up Config: succeeded Sep 24 2020 14:04:16
Runtime Event Log: succeeded Jul 31 2020 07:20:12
Running Config: succeeded Jul 31 2020 07:20:13
ACL Mgr: succeeded Jul 31 2020 07:20:12
LACP: no block sync done
STP: no block sync done
SPAN: no block sync done
CRYPTOMGR: succeeded Jul 31 2020 07:20:12

DELL-SWITCH# show system stack-unit 1

-- Unit 1 --
Unit Type : Management Unit
Status : online
Next Boot : online
Required Type : S3124F - 28-port GE/TE (S3100)
Current Type : S3124F - 28-port GE/TE (S3100)
Master priority : 14
Hardware Rev : 5.0
Num Ports : 30
Up Time : 26 wk, 4 day, 2 hr, 44 min
Dell EMC Networking OS Version : 9.14(2.2)
Jumbo Capable : yes
POE Capable : no
FIPS Mode : enabled
Boot Flash : 5.2.1.8
Boot Selector : Present
Memory Size : 2147483648 bytes
Temperature : 32C
Voltage : ok
Serial Number : NA
Part Number : Rev A00
Vendor Id : DL
Country Code : CN
PPID Revision : A00
Auto Reboot : enabled
No Of MACs : 3

-- Module 1 --
Status : not present

-- Power Supplies --
Unit Bay Status Type FanStatus FanSpeed(rpm)
---------------------------------------------------------------------------
1 1 down UNKNOWN absent 0
1 2 up AC up 0

Unit TotalPower AvgPower AvgPowerStartTime
-------------------------------------------------------
1 38 35.895626 07/31/2020-07:19

-- Fan Status --
Unit Bay TrayStatus Fan1 Speed Fan2 Speed
------------------------------------------------------------------------------------
1 1 up up 5000 up 5000

Speed in RPM

DELL-SWITCH# show system stack-unit 2

-- Unit 2 --
Unit Type : Standby Unit
Status : online
Next Boot : online
Required Type : S3124F - 28-port GE/TE (S3100)
Current Type : S3124F - 28-port GE/TE (S3100)
Master priority : 13
Hardware Rev : 5.0
Num Ports : 30
Up Time : 26 wk, 4 day, 2 hr, 44 min
Dell EMC Networking OS Version : 9.14(2.2)
Jumbo Capable : yes
POE Capable : no
FIPS Mode : enabled
Boot Flash : 5.2.1.8
Boot Selector : Present
Memory Size : 2147483648 bytes
Temperature : 30C
Voltage : ok
Serial Number : NA
Part Number : 0CGMD5 Rev A00
Vendor Id : DL
Country Code : CN
PPID Revision : A00
Auto Reboot : enabled

No Of MACs : 3

-- Module 1 --
Status : not present

-- Power Supplies --
Unit Bay Status Type FanStatus FanSpeed(rpm)
---------------------------------------------------------------------------
2 1 down UNKNOWN absent 0
2 2 up AC up 0

Unit TotalPower AvgPower AvgPowerStartTime
-------------------------------------------------------
2 22 23.342415 07/31/2020-07:19

-- Fan Status --
Unit Bay TrayStatus Fan1 Speed Fan2 Speed
------------------------------------------------------------------------------------
2 1 up up 5000 up 5000

Speed in RPM

DELL-SWITCH#show system brief

Stack MAC :
Reload-Type : normal-reload [Next boot : normal-reload]

-- Stack Info --
Unit UnitType Status ReqTyp CurTyp Version Ports
------------------------------------------------------------------------------------
1 Management online S3124F S3124F 9.14(2.2) 30
2 Standby online S3124F S3124F 9.14(2.2) 30
3 Member not present
4 Member not present
5 Member not present
6 Member not present
7 Member not present
8 Member not present
9 Member not present
10 Member not present
11 Member not present
12 Member not present

-- Module Info --
Unit Module No Status Module Type Ports
---------------------------------------------------------------------------
1 1 not present No Module 0
2 1 not present No Module 0

-- Power Supplies --
Unit Bay Status Type FanStatus FanSpeed(rpm)
---------------------------------------------------------------------------
1 1 down UNKNOWN absent NA
1 2 up AC up NA
2 1 down UNKNOWN absent NA
2 2 up AC up NA

Unit TotalPower AvgPower AvgPowerStartTime
-------------------------------------------------------
1 34 36 07/31/2020-07:19
2 22 23 07/31/2020-07:19

-- Fan Status --
Unit Bay TrayStatus Fan1 Speed Fan2 Speed
------------------------------------------------------------------------------------
1 1 up up 5000 up 5000
2 1 up up 5000 up 5000

Speed in RPM

DELL-SWITCH#

Everything looks fine there, do you only have one power supply on each of the switches?

hey Josh, thank you for your message.

so.. I have 2 failing stacks in different parts of the campus.
In 1 of the stacks I only have 1 PSU per switch, but in the other stack I have 2 PSU per switch connected.

I tried to find anywere in the documentation where this FF comes from, but so far I got nothing.

Any other thoughts before I open a tac case?

I have not been able to find anything about it showing FF either.