using all of raid5 disk space W7x64Pro

Hi,

In a RAID5 configuration, one of the 4 disks is used as the parity data disk, leaving a total of 3 disks for the total volume available.

From http://en.wikipedia.org/wiki/Standard_RAID_levels

RAID 5 usable size
Parity data uses up the capacity of one drive in the array (this can be seen by comparing it with RAID 4: RAID 5 distributes the parity data across the disks, while RAID 4 centralizes it on one disk, but the amount of parity data is the same). If the drives vary in capacity, the smallest of them sets the limit. Therefore, the usable capacity of a RAID 5 array is , where N is the total number of drives in the array and Smin is the capacity of the smallest drive in the array.

See this link as to how it works:

RaidCalc - Raid Disk Space Utilization Calculator - Raid, RAID, Redundancy, Performance - iBeast Business Solutions

Regards,
Golden

Cheers Golden,

I thought that was the case but am now wondering about the odd 277.46GB missing over the amount of the 1tb disk, seems a huge amount of space; though not as much as the 746.54GB that I can actually see and marked as un-allocated but wont let me touch it

[EDIT]

Sorry, just wanted to say thank you for the link to the RaidCalc site, it showed ~211GB would be used so that might be the 277GB I can't account for.

Hi,

The "missing" 277GB is actually used in "creating" the RAID - that is normal, although the actual amount varies a little depending on the disks and RAID controller. See image below.

Can you post a maximised image/screen capture of your Disk management so we can see this unallocated 746GB?

Regards,
Golden

Golden said:

Hi,

In a RAID5 configuration, one of the 4 disks is used as the parity data disk, leaving a total of 3 disks for the total volume available.

From Standard RAID levels - Wikipedia, the free encyclopedia

RAID 5 usable size
Parity data uses up the capacity of one drive in the array (this can be seen by comparing it with RAID 4: RAID 5 distributes the parity data across the disks, while RAID 4 centralizes it on one disk, but the amount of parity data is the same). If the drives vary in capacity, the smallest of them sets the limit. Therefore, the usable capacity of a RAID 5 array is , where N is the total number of drives in the array and Smin is the capacity of the smallest drive in the array.

See this link as to how it works:

RaidCalc - Raid Disk Space Utilization Calculator - Raid, RAID, Redundancy, Performance - iBeast Business Solutions

Regards,
Golden

Just to be clear. It doesn't use a single physical disk for parity. It stripes the data and parity across all four disks so that if one physical disk fails you lose no data.

kado897 said:

Just to be clear. It doesn't use a single physical disk for parity. It stripes the data and parity across all four disks so that if one physical disk fails you lose no data.

Thanks for clearing that up Kado

You are welcome.

Hello Darfy,

Try using Partition Wizard to create a new volume in that space. We'll see if a different program can get the job done.