# UDMA_CRC_Error_Count !



## shahzaib (Sep 11, 2018)

Hi,

Hopes community doing great. We're experiencing disk errors "UDMA_CRC_Error_Count" via smartctl on all of our drives (12 x 3TB) from quite a time now and after trying everything mentioned in this post, we're still not able to diagnose it. Here is the log of smartctl :

https://pastebin.com/sSLqTfzU

The steps we took to fix the problem :

- Changed HDD
- Changed Controller which is Dell PercH200 Flashed in IT mode
- Changed SAS cable

Unfortunately, we're not able to get rid of these errors which are incrementing each day.

Help will highly be appreciated.

Thanks!


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## SirDice (Sep 11, 2018)

It's possible the backplane (which typically also houses the port extender) is a bit dodgy. Cables would be the first thing to try but you already replaced those.

If you can you could try to replace the controller itself. But if that doesn't change anything the only spot where these errors could occur is the port extender since you already replaced everything else.


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## shahzaib (Sep 11, 2018)

SirDice said:


> It's possible the backplane (which typically also houses the port extender) is a bit dodgy. Cables would be the first thing to try but you already replaced those.
> 
> If you can you could try to replace the controller itself. But if that doesn't change anything the only spot where these errors could occur is the port extender since you already replaced everything else.


Thanks for the reply, should i able to replace backplane ? As controller, sas cables are already replaced.


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## SirDice (Sep 11, 2018)

shahzaib said:


> Thanks for the reply, should i able to replace backplane


Probably not. Last time I had an issue with a backplane it was built into the case itself. So the whole machine had to be dismantled and RMA'd. But that machine was brand new, it was still in warranty. 

If you're handy with a screwdriver and have replaced server parts before you might be able to do it yourself. But you will probably have to take the whole thing apart to get to the board.


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## shahzaib (Sep 12, 2018)

Okay our Hardware team just inspected the node and found that SAS expander was not properly connected to Backplane, they have it reconnected it. Will monitor the performance and update here if it fixes or not fixes the issue.


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