extrobe

Patrial Parity Checks

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extrobe    3

Forgive me if I underestimate what might be involved in doing this, but what would be useful is the ability to get partial parity checks as part of regular housekeeping / tasks.

 

Reason being, a full parity check can take a couple of days - what I'd like is to be able to do is set a job which checks a rolling n% per cycle (eg 10% per day).

 

Of course a full parity check for an unclean shutdown etc should probably stay as is, but would definitely like the option to distribute periodic checks to limit them to low-use, low-impact periods.

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descoladan    0

Following up, is there any possibility of having a parity check run over areas of disks that have recently been modified? 

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itimpi    41
3 hours ago, descoladan said:

Following up, is there any possibility of having a parity check run over areas of disks that have recently been modified? 

Not sure what you are asking for here?   Sounds like you want unRAID to track what sectors are being written to and somehow perform a parity check?   Sounds rather complicated!  Note that turning on Turbo write already causes a new parity to be calculated and this is akin to a parity check with correct enabled.

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DireWolf    0

I was also thinking a sort of rolling/sectional parity check for 'off-peak' periods. I would say that you would still require a full parity check at a given schedule but a rolling/sectional check would allow us to decrease the frequency of full parity checks and still give us peace of mind our data is still protected, primarily for the purpose of optimizing system resources.

 

I gather there is probably a lot more to this than I initially suspect and it may not even be viable, but I thought I comment anyway in hopes that someone, more educated than I in this area, could give me an answer to satisfy my curiosity :D

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jonathanm    139
6 hours ago, DireWolf said:

give us peace of mind our data is still protected

Unraid by itself can't do that. Only proper backups to a second physical media can.

 

Parity only protects from one specific failure, a single (or dual if using a second parity drive) failed drive. It doesn't protect against data corruption, accidental deletion, etc.

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DireWolf    0
1 minute ago, jonathanm said:

Unraid by itself can't do that. Only proper backups to a second physical media can.

 

Parity only protects from one specific failure, a single (or dual if using a second parity drive) failed drive. It doesn't protect against data corruption, accidental deletion, etc.

 

Apologies, I was referring to 'data protection' in context to the topic. Maybe a poor choice of wording on my behalf.

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