Raid 5 capacity

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Gilco2

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#233525 19-Apr-2018 17:09

Have an Asustor AS-604T just fitted 4 x 4TB hard drives in raid 5 configuration. In all the raid calculators I can find googling it says should be approx. 12TB useable. I have 10TB useable so just querying if that is indeed normal as just cant find out googling.

HTPC Intel Pentium G3258 cpu, Gigabyte H97n-wifi motherboard, , 8GB DDR3 ram, onboard graphics. Hauppuage HVR 5500 tuner, Silverstone LC16M case, Windows 10 pro 64 bit using Nextpvr and Kodi

timmmay

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#1999432 19-Apr-2018 17:21

Have you considered GB vs GiB?

JimmyH

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#1999465 19-Apr-2018 19:17

They are good units.... I have the 608T.

The basic rule for n drives of a certain size in RAID5 is that you get (n-1) x size of space.

However, your drives are sized in TiB (AKA marketing-speak "weasel terrabytes") not TB which is what windows calculates. The difference is basically 1/(1.024)^3. So 1Tib is approx 0.9TB, and your "4TB" drive is actually about 3.64TB.

You should get about 10.9TB of usable space all up.

But the NAS may be taking some of this for its own purposes, apps, system overhead etc, giving slightly less.

Gilco2

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#1999493 19-Apr-2018 20:03

Thank you. Yeah that explains it. I once saw a formula to work it all out but cant find it now. And having a closer look I see it has put some of its own system on the drives. Not sure but looks like might be drive 1. I like how quiet it also is. Also solid build on these. I bought this in 2013 but cant remember what went wrong now but can remember it being fixed in an update. I got it out again as thought would get drives out of my htpc.

HTPC Intel Pentium G3258 cpu, Gigabyte H97n-wifi motherboard, , 8GB DDR3 ram, onboard graphics. Hauppuage HVR 5500 tuner, Silverstone LC16M case, Windows 10 pro 64 bit using Nextpvr and Kodi