Guess the size of a RAID{5,6} device

Hello,

I'd like to know if it's possible to get the size of a RAID{5,6} which is not created yet but the size of the partitions which will make up the array are.

Thanks
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Quoted 5 lines · On Fri, 11 Apr 2014 10:19:23 +0200 Francis Moreau <[email protected]>…

Hello,

I'd like to know if it's possible to get the size of a RAID{5,6} which is not created yet but the size of the partitions which will make up the array are.

How precise does the "guess" need to be?

If you subtract about 128Meg from the size of the partitions, round down the

a multiple of the chunk size then multiply by the number of data disks, you should come quite close.

Hello Neil,

Quoted 11 lines · NeilBrown

Quoted 5 lines · On Fri, 11 Apr 2014 10:19:23 +0200 Francis Moreau <[email protected]>…

Hello,

I'd like to know if it's possible to get the size of a RAID{5,6} which is not created yet but the size of the partitions which will make up the array are.

How precise does the "guess" need to be?

I just need an approximation in order to report to user some information about the (raided) partition my tool is about to create.

Quoted 1 line

If you subtract about 128Meg from the size of the partitions, round down the

Just to be sure the size of the partitions is equal to the min size of all partitions ?

Quoted 3 lines

a multiple of the chunk size then multiply by the number of data disks, you should come quite close.

Thanks, that should do the trick.