Tag Archives: cosmic rays

How to identify ECC memory modules

This is a short article describing how you proceed to identify whether or not you have ECC memory modules in your Linux workstation or server.

Also as a side note, the importance of ECC memory is great. Even filesystems such as ZFS with check summing will not account for flipped bits due to cosmic rays. According to studies such as http://www.cs.toronto.edu/~bianca/papers/sigmetrics09.pdf , a DIMM has an 8% chance per year of getting a correctable error. Multiply that with the amount of DIMM’s you have in your system (4 or more?), and you suddenly have a very likely chance of seeing data corruption during a year.

To display what type of memory module you have, we make use of the following DMI type:

16   Physical Memory Array

Command

# dmidecode --type 16

Output

# dmidecode 2.11
SMBIOS 2.7 present.

Handle 0x0007, DMI type 16, 23 bytes
Physical Memory Array
        Location: System Board Or Motherboard
        Use: System Memory
        Error Correction Type: Single-bit ECC
        Maximum Capacity: 32 GB
        Error Information Handle: 0x0010
        Number Of Devices: 4

Both on Debian/Ubuntu and RedHat based distributions this tool is provided by the dmidecode package.

// CrashMAG