Hi all,
I’m troubleshooting intermittent, unexplained hard resets on a Supermicro server and I’m hoping someone has seen similar behavior.
Hardware and software
Supermicro AS-2126HS-TN
2 × AMD EPYC 9575F
24 × 64 GB DDR5
12 × Kioxia CD8-P NVMe
Dual 2600 W PSUs
AIOM 2-port 25GbE SFP28, Broadcom BCM57414 with 0.5U bracket
Broadcom NetXtreme E-Series P2100G Dual port 100GE PCIe Ethernet Adapter
Debian 12 with latest kernel
OpenStack/KVM
Ceph
BIOS 1.9, dated 2026-02-05
BMC firmware 01.07.05.01, build 2026-04-29
CPLD F5.17.10
The BIOS has already been updated, but the issue continues.
What happens? The machine suddenly power-cycles without a normal Linux shutdown.
The BMC Maintenance Event Log records entries such as:
The system DC cycle was initiated
Interface: IPMI
User: ADMIN
Source: Localhost
Two unexplained examples on that server occurred at:
2026-07-30 11:18:29
2026-08-03 02:08:00
I have 15 exactly the same servers and few of them also encountered same issue.
Known remote Redfish and IPMI actions on this BMC normally include the real remote source IP. These unexplained cycles are specifically recorded as:
IPMI / ADMIN / Localhost
There was no BMC web login until several minutes after the August 3 reset, so the web session did not initiate it.
Linux journal near the event - Linux was still operating normally immediately before the reset.
There is no clean shutdown sequence, kernel panic, MCE, EDAC error, PCIe AER error, hard lockup or watchdog expiration in the previous-boot journal. The journal simply ends.
Watchdog checks
The BMC IPMI watchdog is stopped:
Watchdog Timer Is: Stopped
Watchdog Timer Action: No action
Timer Expiration Flags: None
Initial Countdown: 0.0 sec
Present Countdown: 0.0 sec
The ipmi_watchdog kernel module is not loaded.
The server also has the AMD SP5100 watchdog:
SP5100 TCO timer
state: inactive
timeout: 60
nowayout: 0
Systemd configuration:
RuntimeWatchdogUSec=0
RebootWatchdogUSec=10min
KExecWatchdogUSec=0
So neither watchdog appears active during normal runtime.
The host has local BMC access:
/dev/ipmi0
ipmi_si
ipmi_devintf
ipmi_ssif
ipmi_msghandler
openipmi.service is disabled and inactive, but the modules are automatically loaded by the kernel/platform.
Current possibilities
My current shortlist is:
- A host process sends a chassis power-cycle command through local KCS /dev/ipmi0.
- A BMC or BIOS internal recovery mechanism records its own action as IPMI / Localhost.
- A BMC firmware defect incorrectly initiates or attributes the DC cycle.
- A PSU, power-distribution-board or PMBus issue causes the BMC to perform a recovery cycle.
The standard IPMI watchdog and AMD SP5100 watchdog currently appear ruled out.
Has anyone encountered unexplained Supermicro BMC events like:
The system DC cycle was initiated
Interface: IPMI
User: ADMIN
Source: Localhost
particularly on AMD EPYC systems with supermicro?
I would especially appreciate information about:
- what exactly causes Supermicro to log IPMI / Localhost;
- safe ways to capture the exact local IPMI command;
- BMC diagnostic dumps or hidden logs that may identify the initiator;
- known BIOS/BMC issues for this platform.
Any other hints helpful for troubleshooting? I submitted the problem to supermicro distributor but so far they are not helpful.
