Author Topic: Parity Size question  (Read 1512 times)

Offline Airbander

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Parity Size question
« on: December 10, 2013, 07:59:00 pm »
Hello

Before you guys lock or shunt me down please look at this screenshots




So it seems that i have 400GB space left but i am going to add 16 TB worth of data to this config so i really dont think 1 4TB drive is enough for 32 TB worth of data

Unless if you guys think i am wrong with my thoughts

I wanted to Span Parity with 1 Main 4TB and 1 Second drive 4TB as Span to be total of 8TB to cover active 24TB +

Thanks in advance

Offline Shadowsoul

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Re: Parity Size question
« Reply #1 on: December 11, 2013, 03:04:17 am »
I think you have misunderstood the way the parity works (or I have completely misunderstood all the FAQs and Wikis).


The parity drive needs to be as large as the largest drive in the pool (or larger), not the entire pool itself.
The pool can be 1000TB and still only need a 100GB parity drive if the pool only has 100GB drives.


So if you add another 16TB of data to your pool you are fine, as long as you add them as separate 4TB drives.
If you use e.g. hardware raid to create 1 volume of 16TB and then add that volume to Flexraid you will need a parity drive that is 16TB.



Offline Airbander

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Re: Parity Size question
« Reply #2 on: December 11, 2013, 12:49:23 pm »
I think you have misunderstood the way the parity works (or I have completely misunderstood all the FAQs and Wikis).


The parity drive needs to be as large as the largest drive in the pool (or larger), not the entire pool itself.
The pool can be 1000TB and still only need a 100GB parity drive if the pool only has 100GB drives.


So if you add another 16TB of data to your pool you are fine, as long as you add them as separate 4TB drives.
If you use e.g. hardware raid to create 1 volume of 16TB and then add that volume to Flexraid you will need a parity drive that is 16TB.

Hi no i got it right i was just concern about 400 GB left from 4TB

Thanks

Offline Quaraxkad

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Re: Parity Size question
« Reply #3 on: December 11, 2013, 07:06:28 pm »
Hi no i got it right i was just concern about 400 GB left from 4TB

Thanks

No, you have misunderstood how parity works. It doesn't matter how much free space you have. You can keep using that one parity drive even for 100TB or more, as long as none of the individual DRUs are larger than the PPU.

Second, don't span anything unless you actually understand what it's for and why you would need it (you don't need it).
« Last Edit: December 11, 2013, 07:08:46 pm by Quaraxkad »

Offline Airbander

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Re: Parity Size question
« Reply #4 on: December 11, 2013, 10:01:10 pm »
Hi

Got it , my issue resolved

Thanks