About 3 years ago I built this system for light server duties (pfsense, ip cameras and backups) and always just assumed that ECC was working fine. Recently I’ve had some problems with VM disks geting corrupted which made me suspicious of the ram and whether or not ECC was working properly.
The corruption problem was simply a dying HD, but it made me fall into the “is-ecc-active-in-my-system” rabbit hole.
From the output of dmidecode -t memory I believe it can only correct one bit errors, but can’t report two bit errors, right?
Also, should’t the Total Width be 72 bits instead of 128?
# dmidecode 3.2
Getting SMBIOS data from sysfs.
SMBIOS 3.0.0 present.
Handle 0x0042, DMI type 16, 23 bytes
Physical Memory Array
Location: System Board Or Motherboard
Use: System Memory
Error Correction Type: Single-bit ECC
Maximum Capacity: 64 GB
Error Information Handle: Not Provided
Number Of Devices: 4
Handle 0x0043, DMI type 17, 40 bytes
Memory Device
Array Handle: 0x0042
Error Information Handle: Not Provided
Total Width: 128 bits
Data Width: 64 bits
Size: 8192 MB
Form Factor: DIMM
Set: None
Locator: DIMM_A1
Bank Locator: BANK 0
Type: DDR4
Type Detail: Synchronous
Speed: 2133 MT/s
Manufacturer: Kingston
Serial Number: 18261514
Asset Tag: 9876543210
Part Number: 9965669-009.A00G
Rank: 2
Configured Memory Speed: 2133 MT/s
Minimum Voltage: Unknown
Maximum Voltage: Unknown
Configured Voltage: 1.2 V
Handle 0x0044, DMI type 17, 40 bytes
Memory Device
Array Handle: 0x0042
Error Information Handle: Not Provided
Total Width: Unknown
Data Width: Unknown
Size: No Module Installed
Form Factor: Unknown
Set: None
Locator: DIMM_A2
Bank Locator: BANK 1
Type: Unknown
Type Detail: None
Speed: Unknown
Manufacturer: Not Specified
Serial Number: Not Specified
Asset Tag: Not Specified
Part Number: Not Specified
Rank: Unknown
Configured Memory Speed: Unknown
Minimum Voltage: Unknown
Maximum Voltage: Unknown
Configured Voltage: Unknown
Handle 0x0045, DMI type 17, 40 bytes
Memory Device
Array Handle: 0x0042
Error Information Handle: Not Provided
Total Width: 128 bits
Data Width: 64 bits
Size: 8192 MB
Form Factor: DIMM
Set: None
Locator: DIMM_B1
Bank Locator: BANK 2
Type: DDR4
Type Detail: Synchronous
Speed: 2133 MT/s
Manufacturer: Kingston
Serial Number: 20262314
Asset Tag: 9876543210
Part Number: 9965669-009.A00G
Rank: 2
Configured Memory Speed: 2133 MT/s
Minimum Voltage: Unknown
Maximum Voltage: Unknown
Configured Voltage: 1.2 V
Handle 0x0046, DMI type 17, 40 bytes
Memory Device
Array Handle: 0x0042
Error Information Handle: Not Provided
Total Width: Unknown
Data Width: Unknown
Size: No Module Installed
Form Factor: Unknown
Set: None
Locator: DIMM_B2
Bank Locator: BANK 3
Type: Unknown
Type Detail: None
Speed: Unknown
Manufacturer: Not Specified
Serial Number: Not Specified
Asset Tag: Not Specified
Part Number: Not Specified
Rank: Unknown
Configured Memory Speed: Unknown
Minimum Voltage: Unknown
Maximum Voltage: Unknown
Configured Voltage: Unknown