How to change BMC SEL mode (Stop on Full or Rollback)

Precaution:

This article is kind of testing case sharing for whom is familiar with IPMI SEL behavior. In case missing any important SEL data when system ran into trouble, the default SEL mode should be in Rollback. Please check the default setting before you change it for testing.

Purpose:

In general, BMC saves system event logs with modes , one is Stop on Full Condition and the other is Wrap on Full Condition (Rollback).  This article will share how to change the mode and how you could test it with simple script.

Target Audience:

User who is using our products with built-in BMC. 

Use Cases:

Scenario 1 :  User will frequently backup SEL to file , then "Stop on Full condition" will keep the STORED SEL data NOT be overwritten by new SEL when SEL is FULL

Scenario 2 :  User is always seeking new SEL info , BMC will keep recording data in SEL and rollback to the beginning of SEL data when it's FULL

How To Change Modes:

Get the current SEL Mode

# ipmitool raw 0x2e 0x62 0x39 0x28 0x00
 39 28 00 01

The last response byte:
0: “Stop on Full Condition”; 1: “Wrap on Full Condition”

Change the SEL Mode to 0 or 1

# ipmitool raw 0x2e 0x62 0x39 0x28 0x00 0x00
39 28 00 00
or
# ipmitool raw 0x2e 0x62 0x39 0x28 0x00 0x01
39 28 00 01

The Default Mode on most of CIoT Platforms (BMC inside) should be 0x01 (Wrap on Full Condition)

Test 

1. Select a mode you would like to check
2. You may refer to this FAQ to generate testing event data to full the SEL
3. Check SEL percent used through "ipmitool sel" 

# ipmitool -I lanplus -H 172.17.10.61 -U administrator -P advantech sel
SEL Information
Version : 1.5 (v1.5, v2 compliant)
Entries : 4095
Free Space : 0 bytes
Percent Used : 100%
Last Add Time : 11/02/2022 07:20:03
Last Del Time : Not Available
Overflow : true
Supported Cmds : 'Reserve' 'Get Alloc Info'
# of Alloc Units : 4095
Alloc Unit Size : 16
# Free Units : 0
Largest Free Blk : 0
Max Record Size : 1

1. Once it get full, check event data is Rollback or Stop at FULL "ipmitool sel elist"

# ipmitool -I lanplus -H 172.17.10.61 -U administrator -P advantech sel elist last 1
fff | 11/02/2022 | 07:20:03 | Event Logging Disabled SYSTEM_EVENT_LOG | Log full | Asserted