Dual parity checks bring server to it's knees


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Hello all,

 

I recently moved to dual parity with 2x 10TB drives. My first monthly parity check began yesterday morning. I noticed when I returned from work that I could not access any of my dockers or the webgui. I tried to access the server via SSH but that failed as well. Pings were also timing out. I did notice that all of the activity LED's were active on the HDD's as if the parity check was still underway. I forced the server down and rebooted, which kicked off another parity check of course. I let this go a while and all seemed well. Until this morning. The parity check was at around 35% and the dockers were really slow to respond and would often time out. The webgui was having the same problem and file transfers to or from the array would not complete. I tried to grab a 2GB file copied to my desktop and it started at full speed and slowed to 0bps. 

 

Before cancelling the parity check I stopped all of my dockers, this did not help. I stopped the parity check and that cleared everything up. What should I be looking at here? Any suggestions would be appreciated. 

 

Thanks!

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4 minutes ago, swells said:

Hello all,

 

I recently moved to dual parity with 2x 10TB drives. My first monthly parity check began yesterday morning. I noticed when I returned from work that I could not access any of my dockers or the webgui. I tried to access the server via SSH but that failed as well. Pings were also timing out. I did notice that all of the activity LED's were active on the HDD's as if the parity check was still underway. I forced the server down and rebooted, which kicked off another parity check of course. I let this go a while and all seemed well. Until this morning. The parity check was at around 35% and the dockers were really slow to respond and would often time out. The webgui was having the same problem and file transfers to or from the array would not complete. I tried to grab a 2GB file copied to my desktop and it started at full speed and slowed to 0bps. 

 

Before cancelling the parity check I stopped all of my dockers, this did not help. I stopped the parity check and that cleared everything up. What should I be looking at here? Any suggestions would be appreciated. 

 

Thanks!

You need to provide your system diagnostics zip file (obtained via Tools->Diagnostics) if you want any feedback which is not random guesses.

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52 minutes ago, trurl said:

Why are you running mover every 3 hours?

 

Why were you running a correcting parity check? Did you have sync errors?

I used to have a much much smaller SSD as my cache drive (200GB), I ran the mover often to keep some room on the cache for downloads, etc. I just never changed this behavior because it has never been a problem. 

 

My scheduled parity check does not do parity corrections. It's possible the auto parity check after an unclean shutdown does? I'm not 100% certain on the behavior of that. 

 

39 minutes ago, Frank1940 said:

You should also read this post from LimeTech:

 

   https://forums.unraid.net/topic/49598-unraid-server-release-620-rc4-available/#comment-487759

 

 

Dual parity calculation is a major CPU hog for any CPU that does not have the AVX2 instruction set.  I don't think yours does.

 

Thanks for this! Indeed it looks like it does not. I might just drop back down to single parity until I upgrade hardware in the future. 

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