Understanding the Parity better


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Hello team!  I am new to this, and had a question for the pros!   

 

1)  I've noticed the the parity drive is writing while the mover is moving.  Is it writing a new parity?  Do I still need to run a parity check after the cache is cleaned out by the mover? 

 

2(  I have about 50TB of storage and two 8TB parity drives on a AMD 8370 w/ 32 gigs ram.  I've noticed that my parity checks are taking 4-5 days to run.  I believe this is due to new data being saved to the server while the parity is running and Plex Docker streaming at the same time.  Correct?

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2 minutes ago, columbuscoltsfan said:

Hello team!  I am new to this, and had a question for the pros!   

 

1)  I've noticed the the parity drive is writing while the mover is moving.  Is it writing a new parity?  Do I still need to run a parity check after the cache is cleaned out by the mover? 

 

2(  I have about 50TB of storage and two 8TB parity drives on a AMD 8370 w/ 32 gigs ram.  I've noticed that my parity checks are taking 4-5 days to run.  I believe this is due to new data being saved to the server while the parity is running and Plex Docker streaming at the same time.  Correct?

Parity is updated at the same time any write occurs to a data disk in the parity array. It doesn't write the whole parity, it just writes the part that corresponds to the data write. Parity checks are not required to keep parity in sync, but many people run them periodically to make sure their parity is good.

 

The time required for a parity check is mostly about how large the parity disk is, not about the total amount of storage. Most people can probably complete an 8TB parity check in less than 1 day, so it sounds like you may have problems. Without rebooting, go to Tools - Diagnostics and post the complete zip.

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Do your USB drives report SMART? Post your diagnostics if you don't know.

 

If they don't then that is an important issue in addition to the performance issue.

 

Even though unRAID "officially" supports USB disks in the array, I don't think many use this approach due to these concerns.

 

Is there some reason you decided to do it this way?

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