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Solved Storage Spaces Capacity (RAID5)


jfd514

New Member
Posts
3
#1
Hi everyone, I've been using storage space for around a year with pool and raid functionality and I just realized the numbers don't add up... I have 7x 2TB all parts of a single pool with parity. Now here's the numbers:

Physical space: 14tb
Storage Space size (user set): 12tb
Used Storage Space size (according to windows explorer): ~6tb
Used Storage Space size (according to storage spaces): ~9tb
Individual drive used % (according to storage spaces): ~75% each

Storage spaces tells me to add a drive, low capacity... So I know how normal RAID5 works and it really shouldn't use 50% of the total used space as shown by the numbers above (6tb + 3tb assumed to be parity = 9tb). Also, if I need to add another drive, this means I'm almost full at 6tb/14tb?! This is worst than MIRROR RAID...

Am I reading it wrong?
 

My Computer

System One

  • OS
    Windows 8 Pro
    Computer type
    PC/Desktop
    CPU
    Intel i7 2600K

Mystere

Power User
VIP Member
Power User
Posts
1,925
#2
Storage Spaces is not RAID5.

It is more akin to the old PAR archive system they used to use for transferring binaries over usenet. You can also over-commit. That is, you can define more disk space than you actually have, and then just add more drives as you increase space.
 

My Computer

System One

  • OS
    Windows 8.1 Pro
    CPU
    Intel i7 3770K
    Motherboard
    Gigabyte Z77X-UD4 TH
    Memory
    16GB DDR3 1600
    Graphics Card(s)
    nVidia GTX 650
    Sound Card
    Onboard Audio
    Monitor(s) Displays
    Auria 27" IPS + 2x Samsung 23"
    Screen Resolution
    2560x1440 + 2x 2048x1152
    Hard Drives
    Corsair m4 256GB, 2 WD 2TB drives
    Case
    Antec SOLO II
    Keyboard
    Microsoft Natural Ergonomic Keyboard 4000
    Mouse
    Logitech MX

jfd514

New Member
Posts
3
#3
Sorry if my question was not precise enough. "Why is windows 8 storage spaces taking more than 100% of total used data size for parity? (Making it less space efficient and of course less reliable than mirror raid).

I know I can increase the total pool size and add more drives, I'm just wondering why on a 14tb pool with parity I get to use only ~6tb. It doesn't make any sense, how can parity use up more space than a mirror?!
 

My Computer

System One

  • OS
    Windows 8 Pro
    Computer type
    PC/Desktop
    CPU
    Intel i7 2600K

Mystere

Power User
VIP Member
Power User
Posts
1,925
#4

My Computer

System One

  • OS
    Windows 8.1 Pro
    CPU
    Intel i7 3770K
    Motherboard
    Gigabyte Z77X-UD4 TH
    Memory
    16GB DDR3 1600
    Graphics Card(s)
    nVidia GTX 650
    Sound Card
    Onboard Audio
    Monitor(s) Displays
    Auria 27" IPS + 2x Samsung 23"
    Screen Resolution
    2560x1440 + 2x 2048x1152
    Hard Drives
    Corsair m4 256GB, 2 WD 2TB drives
    Case
    Antec SOLO II
    Keyboard
    Microsoft Natural Ergonomic Keyboard 4000
    Mouse
    Logitech MX

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