What are the risks when using a known faulty memory module with Unraid?

[misterbeetz]

I am currently in process of building an additional Unraid server out of spare parts and noticed that one of the two memory modules that I intended to use is failing memtest.  I have heard conflicting opinions on this issue as to the type and severity of the risks associated with using such a failed module regardless with Unraid.  Can someone who is knowledgeable on this topic be able to comment on these risks?  For example would the chances of file corruption increase on the protected array in this scenario?

 

For reference the memory I have in mind is of the non-ecc variety.  One 8gb sticks fails memtest while the other 8gb stick passes memtest.  Recently I have heard comments that I should be able to use both sticks of memory with Unraid without causing an increased chance of file corruption on the array.  Is that true?

[itimpi]

Using faulty memory is highly likely to result in frequent server crashes.    It can also cause random data corruption.   You should NOT use RAM modules that fail memtest.

[misterbeetz]

11 minutes ago, itimpi said:

Using faulty memory is highly likely to result in frequent server crashes.    It can also cause random data corruption.   You should NOT use RAM modules that fail memtest.

 

Thanks for the response.  The server crash aspect would certainly be a concern.  Suppose however that in this (hypothetical) instance the server appears to be consistently stable and is not crashing.  Would there still be an increased risk in data corruption on the protected array as a result of the faulty (non-ecc) memory module?

[itimpi]

1 minute ago, misterbeetz said:

 

Thanks for the response.  The server crash aspect would certainly be a concern.  Suppose however that in this (hypothetical) instance the server appears to be consistently stable and is not crashing.  Would there still be an increased risk in data corruption on the protected array as a result of the faulty (non-ecc) memory module?

If you do not get crashes you are still highly likely to get data corruption as all disk access goes via RAM.    If on a btrfs format drive this would later be detected and the drive forced read-only but the file data would still be corrupt and only recoverable from your backups.    If on a XFS formatted drive the corruption might not be noticed unless it resulted in file metadata corruption.

 

the bottom line is you NEVER want to run with faulty RAM as it is almost certain to cause you serious problems.

[foo_fighter]

In my case, silent file corruptions and corrupted USB stick on reboots or shutdowns. Please don't use a faulty memory module. 

[misterbeetz]

11 hours ago, itimpi said:

If you do not get crashes you are still highly likely to get data corruption as all disk access goes via RAM.    If on a btrfs format drive this would later be detected and the drive forced read-only but the file data would still be corrupt and only recoverable from your backups.    If on a XFS formatted drive the corruption might not be noticed unless it resulted in file metadata corruption.

 

the bottom line is you NEVER want to run with faulty RAM as it is almost certain to cause you serious problems.

 

Thank you for clarifying, this is great information.  To wrap this up I am going to reference the comment that inspired me to start this thread for my own informational purposes.  Suppose you encounter someone outside of these forums who is familiar with Unraid and has used it previously.  Suppose they come along and say the following: "[you can safely use the faulty memory in your Unraid system going forward] as memory is not used for any RAID activity, so unless you are mounting this as non volatile cache disk I can't see any of your data damaged or compromised "

 

What would your response be in that instance?  Are they possibly getting mixed up with a different raid-like system where such a statement could be true? 

Edited November 15, 2022 by misterbeetz
Added clarifications in [...]

[klipp01]

still highly likely to get data corruption as all disk access goes via RAM.

This from an above post. The OS runs loads and runs in RAM

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