I’m attempting to shape my RAID to an all 2TB 3-block device array. My current array is as follows:
/dev/sda1 3TB active clean ==>> /dev/sda1 796GB
/dev/sdc1 2TB active clean
/dev/sdd1 2TB active clean
/dev/sde 1TB active clean ==>> –fail then –remove
My goal is to end up with a 4TB RAID array with 3 devices. Then use the “free” partitions /dev/sde and /dev/sda1 to create another RAID array later.
$mdadm /dev/md127 –fail /dev/sda1 ##to set the block device as fail
$mdadm /dev/md127 –remove /dev/sda1 ##to remove the block device from the array
$mdadm –detail /dev/md127 ##to check the array status, note the status of each of the component devices
You should see that one block device is removed now. I can start partitioning /dev/sda1 with fdisk.
$fdisk /dev/sda ##to load the device
If you have not used fdisk before, it is command line only but everything is easy to get.
$ sudo fdisk /dev/sda ##to load the device, give your root password
[sudo] password for donato:
Welcome to fdisk (util-linux 2.31).
Changes will remain in memory only, until you decide to write them. Be careful before using the write command.
Command (m for help): m
d delete a partition
F list free unpartitioned space
l list known partition types
n add a new partition
p print the partition table
t change a partition type
v verify the partition table
i print information about a partition
m print this menu
x extra functionality (experts only)
I load disk layout from sfdisk script file
O dump disk layout to sfdisk script file
Save & Exit
w write table to disk and exit
q quit without saving changes
Create a new label
g create a new empty GPT partition table
G create a new empty SGI (IRIX) partition table
o create a new empty DOS partition table
s create a new empty Sun partition table
Create a new empty GPT partition table. This will set up deletion of all partitions and data on the device. Only when you type w is everything written to disk. So think before typing w.
I want to add a new partition. Type n to create a partition. I want to have a 2TB partition and the rest to another partition.
When asked for the type, type 29. I’m going to use these partitions in an array.
Command (m for help): p
Disk /dev/sda: 2.7 TiB, 3000592982016 bytes, 5860533168 sectors Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 4096 bytes
I/O size (minimum/optimal): 4096 bytes / 4096 bytes
Disklabel type: gpt
Disk identifier: C8877BCC-89D4-F84A-A427-46A4D2886055
Device Start End Sectors Size Type
/dev/sda1 4294969344 5860533134 1565563791 746.5G Linux RAID /dev/sda2 2048 4294969343 4294967296 2T Linux RAID
Partition table entries are not in disk order.
The partition seemed fine to me. So I made it permanent by typing w then q to exit fdisk.