2012r2 dual parity virtual disk capacity incorrect


i have 2012r2 storage server 12x 6tb hdd. drives shows 5.46 tb capacity expected. unexpected creating array in powershell. setup 12 drives single dual parity space. using command

new-virtualdisk -storagepoolfriendlyname 72tb -friendlyname hdd_parity -usemaximumsize -resiliencysettingname parity -provisioningtype fixed -physicaldiskredundancy 2 

i reported capacity of 48.88 tb. using n-2 x 5.46 tb should see 54.6 tb 48.88 / 9 = 5.43 tb or n-3. specifying columns manually @ 12 gives same results, columns 11 drops capacity 1 more drive , on.

if switch routes , use

new-virtualdisk -storagepoolfriendlyname 72tb -friendlyname hdd_parity -usemaximumsize -resiliencysettingname parity -provisioningtype fixed -physicaldiskredundancy 1 -numberofcolumns 6 

which if not mistaken 2x 6 drive single parity arrays striped or spanned? 54.57 tb aligns n-1 x 2 or 5.46 tb x 10.

so missing drive dual parity virtual drive? it's not reported hot spare , rather not throw away capacity of third drive isn't being used in conceivable way.


hi,

dual parity virtual drive requires 3 columns store “parity” information. storage spaces uses erasure coding dual parity scheme, optimizes recovery common case (single disk failure). comes @ cost of higher overhead, 3 columns of “parity” information instead of traditional 2.

more detailed information, please refer thread below:

space calculation dual dual parity volume
https://social.technet.microsoft.com/forums/en-us/1b27c699-80f0-4b8c-887f-779f0e5fedc8/space-calculation-with-dual-dual-parity-volume?forum=winserver8gen

best regards,

mandy

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Windows Server  >  File Services and Storage



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