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XYNaPSE 02-02-2017 07:58 PM
Setting up RAID10 question/issue
 
Hello,

I have a CENTOS 7 server with 4 120GB SSD drives. RAID10 is being used. To my understanding of RAID10 I thought 240GB would be available but only 120GB is showing. I have never set up RAID before so if this needs to be moved to the newb section I understand. If someone could help me understand. I do see the 4 drives listed. I'm thinking one needs to be mounted and I'm not sure which one or I'm wrong about being able to use 240GB. Thank you in advance for responses.

Code:
[root@web1 ~]# df -h
Filesystem      Size  Used Avail Use% Mounted on
/dev/md1        117G  9.8G  101G  9% /
devtmpfs        7.8G    0  7.8G  0% /dev
tmpfs          7.8G    0  7.8G  0% /dev/shm
tmpfs          7.8G  33M  7.8G  1% /run
tmpfs          7.8G    0  7.8G  0% /sys/fs/cgroup
/dev/md0      1007M  138M  819M  15% /boot
tmpfs          1.6G    0  1.6G  0% /run/user/0
Code:
[root@web1 ~]# mdadm --examine --scan
ARRAY /dev/md/0  metadata=1.0 UUID=a693e28d:189b0726:faa3dce2:16eb2f11 name=web1.quantumspider.com:0
ARRAY /dev/md/1  metadata=1.2 UUID=04d77c92:7650f23e:836ca662:be05e9ab name=web1.quantumspider.com:1
Code:
/dev/md0:
        Version : 1.0
  Creation Time : Wed Feb  1 22:22:12 2017
    Raid Level : raid1
    Array Size : 1047488 (1022.94 MiB 1072.63 MB)
  Used Dev Size : 1047488 (1022.94 MiB 1072.63 MB)
  Raid Devices : 4
  Total Devices : 4
    Persistence : Superblock is persistent

  Intent Bitmap : Internal

    Update Time : Thu Feb  2 23:59:13 2017
          State : clean
 Active Devices : 4
Working Devices : 4
 Failed Devices : 0
  Spare Devices : 0

          Name : web1.quantumspider.com:0  (local to host web1.quantumspider.com)
          UUID : a693e28d:189b0726:faa3dce2:16eb2f11
        Events : 23

    Number  Major  Minor  RaidDevice State
      0      8        2        0      active sync  /dev/sda2
      1      8      18        1      active sync  /dev/sdb2
      2      8      34        2      active sync  /dev/sdc2
      3      8      50        3      active sync  /dev/sdd2
Code:
[root@web1 ~]# mdadm --detail /dev/md1
/dev/md1:
        Version : 1.2
  Creation Time : Wed Feb  1 22:21:18 2017
    Raid Level : raid1
    Array Size : 123919360 (118.18 GiB 126.89 GB)
  Used Dev Size : 123919360 (118.18 GiB 126.89 GB)
  Raid Devices : 4
  Total Devices : 4
    Persistence : Superblock is persistent

  Intent Bitmap : Internal

    Update Time : Thu Feb  2 20:51:44 2017
          State : clean
 Active Devices : 4
Working Devices : 4
 Failed Devices : 0
  Spare Devices : 0

          Name : web1.quantumspider.com:1  (local to host web1.quantumspider.com)
          UUID : 04d77c92:7650f23e:836ca662:be05e9ab
        Events : 536

    Number  Major  Minor  RaidDevice State
      0      8        3        0      active sync  /dev/sda3
      1      8      19        1      active sync  /dev/sdb3
      2      8      35        2      active sync  /dev/sdc3
      3      8      51        3      active sync  /dev/sdd3
Code:
[root@web1 ~]# fdisk -l

Disk /dev/sdc: 128.0 GB, 128035676160 bytes, 250069680 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk label type: dos
Disk identifier: 0x0002fbc0

  Device Boot      Start        End      Blocks  Id  System
/dev/sdc1            2048        4095        1024  83  Linux
/dev/sdc2  *        4096    2099199    1047552  fd  Linux raid autodetect
/dev/sdc3        2099200  250068991  123984896  fd  Linux raid autodetect

Disk /dev/sdb: 128.0 GB, 128035676160 bytes, 250069680 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk label type: dos
Disk identifier: 0x000028d1

  Device Boot      Start        End      Blocks  Id  System
/dev/sdb1            2048        4095        1024  83  Linux
/dev/sdb2  *        4096    2099199    1047552  fd  Linux raid autodetect
/dev/sdb3        2099200  250068991  123984896  fd  Linux raid autodetect

Disk /dev/sdd: 128.0 GB, 128035676160 bytes, 250069680 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk label type: dos
Disk identifier: 0x0005a213

  Device Boot      Start        End      Blocks  Id  System
/dev/sdd1            2048        4095        1024  83  Linux
/dev/sdd2  *        4096    2099199    1047552  fd  Linux raid autodetect
/dev/sdd3        2099200  250068991  123984896  fd  Linux raid autodetect

Disk /dev/sda: 128.0 GB, 128035676160 bytes, 250069680 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk label type: dos
Disk identifier: 0x000c9a7d

  Device Boot      Start        End      Blocks  Id  System
/dev/sda1            2048        4095        1024  83  Linux
/dev/sda2  *        4096    2099199    1047552  fd  Linux raid autodetect
/dev/sda3        2099200  250068991  123984896  fd  Linux raid autodetect

Disk /dev/md1: 126.9 GB, 126893424640 bytes, 247838720 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes


Disk /dev/md0: 1072 MB, 1072627712 bytes, 2094976 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes

syg00 02-02-2017 08:10 PM
RAID1 perhaps ?. Check the listings you provided.

XYNaPSE 02-02-2017 08:26 PM
Quote:
Originally Posted by syg00 (Post 5664241)
RAID1 perhaps ?. Check the listings you provided.
I see it does say RAID1 but even then shouldn't it show 240GB available? Sorry I'm lost. :D:redface:

To my understanding in RAID 10, 2 sets of 2 drives each will use Raid 1 while those 2 sets of drives use RAID 0 and that is how RAID 10 works and why 4 drives are required. So I thought that 240GB would be available as 2 drives 120GB each.

The datacenter I'm using has the option to provision the server. I chose Centos7 with Soft Raid 10 (4 disks sda sdb sdc sdd)

XYNaPSE 02-02-2017 08:59 PM
I think I understand now. It must have not setup RAID10 and I will have to start over.

mdadm --detail /dev/md0
mdadm --detail /dev/md1

Should both show Raid Level : RAID 10 but instead show RAID 1

syg00 02-02-2017 09:01 PM
RAID1 isn't RAID10.
RAID1 has no striping, so you will get 4 copies of the data - one plus 3 mirrors. Size is limited to (smallest) extent size.

Edit: looks like our posts crossed "in flight".

XYNaPSE 02-02-2017 09:23 PM
Quote:
Originally Posted by syg00 (Post 5664264)
RAID1 isn't RAID10.
RAID1 has no striping, so you will get 4 copies of the data - one plus 3 mirrors. Size is limited to (smallest) extent size.

Edit: looks like our posts crossed "in flight".
Ok thank you. :) Back to square 1.

XYNaPSE 02-03-2017 03:01 PM
The problem was the datacenter had an error in the installation profile. It has been corrected. Kudos to me for trying to figure it out with out bothering IT support. :cool: In the end it was inevitable. Anyway, I learned a lot more about RAID because of it.


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