Detecting ECC memory

[SimpleSample]

Hi,

My current host is supposed to provide ECC memory for my hosting plan as per the service description.

But while checking the ECC status through dmidecode, I was not able to ascertain if that is so. Command result from dmidecode:

$ dmidecode --type memory
...
Memory Device
Array Handle: 0x003A
Error Information Handle: Not Provided
Total Width: 72 bits
Data Width: 64 bits
Size: 1024 MB
Form Factor: DIMM
Set: None
Locator: P1-DIMM1A
Bank Locator: BANK0
Type: Other
Type Detail: Other
Speed: 1333 MHz
Manufacturer: Manufacturer00
Serial Number: 00000000
Asset Tag: AssetTagNum0
Part Number: SUPERTALENT02
Rank: Unknown
...

I have verified that both motherboards and memory modules have ECC. The motherboard is supermicro X8DT3 and the memory modules are supertalent W13RA1G8x.

Since commands like dmidecode are not displaying the ECC status, I am bit concerned whether the server actually has ECC capability. Is this a genuine concern?

[zomgmike]

DMIDecode isn't 100% reliable for telling what hardware is in a machine. It's a display of what the OS is being told is present by the BIOS which may or may not be a correct list of what is actually there. According to Linus Torvalds, "The only thing the kernel really uses DMI for tends to be to black-list certain motherboards." I interpret that to mean that what DMIdecode says has little to do with whether or not you're getting the full horsepower you paid for.

From the dmidecode readme file:

Beware that DMI data have proven to be too unreliable to be blindly trusted.
Dmidecode does not scan your hardware, it only reports what the BIOS told it
to.

Do you have IMPI access?

[Communism]

Total Width: 72 bits
Data Width: 64 bits

I'm assuming this will determine ECC or not, if total Width is higher than data width, its gotta be doing something with it, in this case, its used for ECC


From Wikipedia

Total module capacity is a product of one chip's capacity by the number of chips. ECC modules multiply it by 8/9 because they use one bit per byte for error correction. A module of any particular size can therefore be assembled either from 32 small chips (36 for ECC memory), or 16(18) or 8(9) bigger ones.

DDR memory bus width per channel is 64 bits (72 for ECC memory). Total module bit width is a product of bits per chip by number of chips. It also equals number of ranks (rows) multiplied by DDR memory bus width. Consequently a module with greater amount of chips or using ×8 chips instead of ×4 will have more ranks.

[Sheps]

Thanks for the post Communism, I would not have known how to figure that out myself from the data he posted.

I always enjoy learning something new especially when it is related to technology.

[SimpleSample]

Thanks zomgmike, Communism for the valuable insights. It totally escaped my observation that the total width is higher than the data width.

[Communism]

First you blame a command that worked perfectly.
Then you probably wasted your host's time complaining about something that wasn't wrong.
And now you're saying you knew all along after you're told how it works.
I love the internets.

[Coolraul]

First you blame a command that worked perfectly.
Then you probably wasted your host's time complaining about something that wasn't wrong.
And now you're saying you knew all along after you're told how it works.
I love the internets.

Even though this was kind of mean, I have to admit thats exactly what crossed my mind when I read this thread. But I am too nice to say mean things like that