Issue with RAID

[CrazYmonkeY159]

I just purchased 2 x 3TB HDDs and wanted to raid them so what I did was allocate the partitions and format them. After doing so I double checked the reported capacity of my drives. They were still 3 TB

Now when ran the mdadm raid command to make a raid 1 volume, all was fine until I checked my volume size again.

When running mdadm --detail /dev/md0 I get

/dev/md0:
        Version : 1.2
  Creation Time : Wed Jul 31 17:19:44 2013
     Raid Level : raid1
     Array Size : 782651648 (746.39 GiB 801.44 GB)
  Used Dev Size : 782651648 (746.39 GiB 801.44 GB)
   Raid Devices : 2
  Total Devices : 2
    Persistence : Superblock is persistent

    Update Time : Wed Jul 31 19:25:09 2013
          State : active, resyncing
 Active Devices : 2
Working Devices : 2
 Failed Devices : 0
  Spare Devices : 0

  Resync Status : 17% complete

           Name : xxx:0  (local to host xxx)
           UUID : 8a02c09f:5a8e78dc:7bc5286e:a44db527
         Events : 17

    Number   Major   Minor   RaidDevice State
       0       8       17        0      active sync   /dev/sdb1
       1       8       33        1      active sync   /dev/sdc1

As you can see the raid partition is 700GB
(omitted Name to xxx for obv reasons) any help as to what I did wrong

 

[Gnome]

I assume when you say 3 disks you mean RAID 1 + a hot spare?

 

[Sinbad]

I assume when you say 3 disks you mean RAID 1 + a hot spare?

Indeed. Raid 1 uses pairs.
You should probably use raid 5

 

[ginggs]

I assume when you say 3 disks you mean RAID 1 + a hot spare?

Who said 3 disks?

 

[bin3]

2 disks - can only mirror or stripe.

all things being equal, you might have missed specifying the size parameter, and it might have defaulted to sectors vs bits.

try using a gui tool first maybe? most distributions have a way of creating a raid either via the gui or via the install.

 

[Sinbad]

Who said 3 disks?

Damn.

 

[CrazYmonkeY159]

Problem found. Used fdisk to create my partitions. Only 2TB and below I am told, this does not explain why I only got 700GB though.

 

[bullzeye.za]

Problem found. Used fdisk to create my partitions. Only 2TB and below I am told, this does not explain why I only got 700GB though.

Probably got the second partition ( which will be the remainder, 2.7TB - 2TB ) and raided those.

 

[Tinuva]

Problem found. Used fdisk to create my partitions. Only 2TB and below I am told, this does not explain why I only got 700GB though.

Really? I remember I couldn't do this on Windows and specifically went into Linux and used fdisk to create my 3TB drives as single partitions.

 

[CrazYmonkeY159]

Really? I remember I couldn't do this on Windows and specifically went into Linux and used fdisk to create my 3TB drives as single partitions.

After some painful googling this is what I came across, seemed to fit my problem. Everything is fine now. Yeah bullzeye I did get the 2nd partition. All's well now used parted and mdadm to get my raid up.