Triple Parity


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Sorry if this has been asked before.  Dual parity just isn't enough with large arrays.  I've had to replace 2 disks a couple of times now, and having the extra peace of mind with that one extra disk would be amazing.

 

I know it's likely a big CPU overhead with the maths calculations, but if you could give people the choice, who have the hardware to do it, that would be amazing

 

Once you hit 14+ drives, the chance for an additional failure whilst rebuilding must skyrocket

 

thanks!

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Easier said than done.  It's not easy to back up 100+TB of data

 

My important stuff is backed up according to the 321 strategy, but movies and tv shows which take up a huge amount of space can't easily be backed up.  Triple parity would at least give some additional peace of mind when swapping faulty disks. (it took some nagging to persuade my wife to let me but 14 x 14TB external drives!)

Edited by sdamaged
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nth parity seems like something that should be up to the user, so i'd vote for an nth parity option.  Is it more complicated programatically to add n vs 3?  Seems to be the best if it was uncapped and people can have between 0 and n if they wish.

 

ATM I'm happy with 2 but I can see why its a bit nerve racking if you have multiple SAS enclosures.

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  • 7 months later...

I need it badly. 234 TB and 28 data drives with dual parity. I’d prefer multiple drive arrays, but will take anything I can get. I have multiple onsite, offsite, and cloud  backups of the most critical 14 TB of data, but that leaves a tremendous amount remaining. I’ve been adding to a second backup server over time and between the 2, having a FULL onsite backup we are quickly approaching 500 TB.

 

Finally, we run our media production company on UNRAID and high quality raw 4K footage is no joke space-wise. A single video project can be 1 TB by itself.

 

Looking forward to the future of UNRAID!

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  • 4 months later...

Apologies if it's against the rules to necro a thread but i'm adding a vote for a triple parity array.

 

I installed 2 brand new Toshiba 6TB drives into my array and both threw up errors. My VM's disappeared, Dockers crashed, everything ceased to function. I am currently biting my nails watching the array rebuild itself. I fear some of my older 8TB drives will give up during the rebuild.

 

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Edited by LumpyCustard
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  • 1 year later...
  • 5 months later...

my understanding of finite fields is limited but i think the calculation for a nth parity would merely involve calculating disk number to the nth power in one.  not sure how much more overhead this would be than the 2nd power like it is now for dual parity.  if it isn't prohibitive i would like to be able to add a 3rd parity

Edited by duelistjp
needed more
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  • 5 months later...
2 minutes ago, tazman said:

+1. I am running 22 mostly 4TB data drives with overall 82T I also experienced dual drive failure for the second time recently. Surely a nail biting and nerve wrecking experience I do not want to go through again.

Personally I think this is unlikely to happen as it provides marginal safety improvement as the chance of triple drive failure are so small that Limetech will probably not invest the development effort required.  When Unraid  6.13 arrives you could split your current array into 2 smaller ones each of which could then have dual parity.

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