How to increase size of RAID1 in Linux !

This summer I had to raise a raid partition from 1 TB to 2 TB.
I found some information, put link down.
This video explain how to increase size:
A good start for information:
https://www.howtoforge.com/how-to-resize-raid-partitions-shrink-and-grow-software-raid-p2
https://raid.wiki.kernel.org/index.php/A_guide_to_mdadm
I will show my steps:
Details
[root@dc ~]# mdadm --detail /dev/md2 /dev/md2: Version : 1.1 Creation Time : Wed Jul 16 16:28:06 2014 Raid Level : raid1 Array Size : 972009280 (926.98 GiB 995.34 GB) Used Dev Size : 972009280 (926.98 GiB 995.34 GB) Raid Devices : 2 Total Devices : 2 Persistence : Superblock is persistent
Intent Bitmap : Internal

Update Time : Wed Jul 19 17:15:01 2017
      State : active

Active Devices : 2

Working Devices : 2

Failed Devices : 0

Spare Devices : 0
       Name : serverp0.probiting.ro:2
       UUID : 20c27ff9:81cb1db1:91f3d123:77844d9c
     Events : 82177

Number   Major   Minor   RaidDevice State
   3       8       19        0      active sync   /dev/sdb3
   2       8        3        1      active sync   /dev/sda3


Partition /dev/sda3

<co[root@dc ~]# fdisk -l /dev/sda3
Disk /dev/sda3: 995.5 GB, 995471917056 bytes

255 heads, 63 sectors/track, 121025 cylinders

Units = cylinders of 16065 * 512 = 8225280 bytes

Sector size (logical/physical): 512 bytes / 4096 bytes

I/O size (minimum/optimal): 4096 bytes / 4096 bytes

Disk identifier: 0xfffefffede>

Partition /dev/sdb3

[root@dc ~]# fdisk -l /dev/sdb3
Disk /dev/sdb3: 995.5 GB, 995471917056 bytes

255 heads, 63 sectors/track, 121025 cylinders

Units = cylinders of 16065 * 512 = 8225280 bytes

Sector size (logical/physical): 512 bytes / 4096 bytes

I/O size (minimum/optimal): 4096 bytes / 4096 bytes

Disk identifier: 0xfffefffe

Fist step: fail one partition and remove, afther this grow partition.

[root@dc ~]# mdadm --manage /dev/md2 --fail /dev/sdb3

[root@dc ~]# mdadm --manage /dev/md2 --remove /dev/sdb3 
Result:



[root@dc ~]# cat /proc/mdstat

Personalities : [raid1]

md0 : active raid1 sda1[2] sdb1[3]

524224 blocks super 1.0 [2/2] [UU]
md2 : active raid1 sda3[2]

972009280 blocks super 1.1 [2/1] [_U]

bitmap: 5/8 pages [20KB], 65536KB chunk

md1 : active raid1 sdb2[3] sda2[2]

4093888 blocks super 1.1 [2/2] [UU]


Remove raid block

 [root@dc ~]# mdadm --zero-superblock /dev/sdb3 

Now change size on /dev/sdb3

 [root@dc ~]# fdisk /dev/sdb
The device presents a logical sector size that is smaller than

the physical sector size. Aligning to a physical sector (or optimal

I/O) size boundary is recommended, or performance may be impacted.

WARNING: DOS-compatible mode is deprecated. It's strongly recommended to

switch off the mode (command 'c') and change display units to

sectors (command 'u').
Command (m for help): p
Disk /dev/sdb: 2000.4 GB, 2000398934016 bytes

255 heads, 63 sectors/track, 243201 cylinders

Units = cylinders of 16065 * 512 = 8225280 bytes

Sector size (logical/physical): 512 bytes / 4096 bytes

I/O size (minimum/optimal): 4096 bytes / 4096 bytes

Disk identifier: 0x00000000
Device Boot      Start         End      Blocks   Id  System

/dev/sdb1   *           1          66      524288   fd  Linux raid autodetect

Partition 1 does not end on cylinder boundary.

/dev/sdb2              66         576     4096000   fd  Linux raid autodetect

Partition 2 does not end on cylinder boundary.

/dev/sdb3             576      121602   972140544   fd  Linux raid autodetect
Command (m for help): d

Partition number (1-4): 3
Command (m for help): p
Disk /dev/sdb: 2000.4 GB, 2000398934016 bytes

255 heads, 63 sectors/track, 243201 cylinders

Units = cylinders of 16065 * 512 = 8225280 bytes

Sector size (logical/physical): 512 bytes / 4096 bytes

I/O size (minimum/optimal): 4096 bytes / 4096 bytes

Disk identifier: 0x00000000
Device Boot      Start         End      Blocks   Id  System

/dev/sdb1   *           1          66      524288   fd  Linux raid autodetect

Partition 1 does not end on cylinder boundary.

/dev/sdb2              66         576     4096000   fd  Linux raid autodetect

Partition 2 does not end on cylinder boundary.
Command (m for help): n

Command action

e   extended

p   primary partition (1-4)

p

Partition number (1-4): 3

First cylinder (576-243201, default 576):

Using default value 576

Last cylinder, +cylinders or +size{K,M,G} (576-243201, default 243201):

Using default value 243201
Command (m for help): p
Disk /dev/sdb: 2000.4 GB, 2000398934016 bytes

255 heads, 63 sectors/track, 243201 cylinders

Units = cylinders of 16065 * 512 = 8225280 bytes

Sector size (logical/physical): 512 bytes / 4096 bytes

I/O size (minimum/optimal): 4096 bytes / 4096 bytes

Disk identifier: 0x00000000
Device Boot      Start         End      Blocks   Id  System

/dev/sdb1   *           1          66      524288   fd  Linux raid autodetect

Partition 1 does not end on cylinder boundary.

/dev/sdb2              66         576     4096000   fd  Linux raid autodetect

Partition 2 does not end on cylinder boundary.

/dev/sdb3             576      243201  1948890720+  83  Linux
Command (m for help): t

Partition number (1-4): 3

Hex code (type L to list codes): fd

Changed system type of partition 3 to fd (Linux raid autodetect)
Command (m for help): p
Disk /dev/sdb: 2000.4 GB, 2000398934016 bytes

255 heads, 63 sectors/track, 243201 cylinders

Units = cylinders of 16065 * 512 = 8225280 bytes

Sector size (logical/physical): 512 bytes / 4096 bytes

I/O size (minimum/optimal): 4096 bytes / 4096 bytes

Disk identifier: 0x00000000
Device Boot      Start         End      Blocks   Id  System

/dev/sdb1   *           1          66      524288   fd  Linux raid autodetect

Partition 1 does not end on cylinder boundary.

/dev/sdb2              66         576     4096000   fd  Linux raid autodetect

Partition 2 does not end on cylinder boundary.

/dev/sdb3             576      243201  1948890720+  fd  Linux raid autodetect
Command (m for help): w

The partition table has been altered!
Calling ioctl() to re-read partition table. 
Now add new raid device.

 [root@dc ~]# cat /proc/mdstat

Personalities : [raid1]

md0 : active raid1 sda1[2] sdb1[3]

524224 blocks super 1.0 [2/2] [UU]
md2 : active raid1 sda3[2]

972009280 blocks super 1.1 [2/1] [_U]

bitmap: 5/8 pages [20KB], 65536KB chunk

md1 : active raid1 sdb2[3] sda2[2]

4093888 blocks super 1.1 [2/2] [UU]
[root@dc ~]# mdadm -a /dev/md2 /dev/sdb3

mdadm: added /dev/sdb3

[root@dc ~]# cat /proc/mdstat

Personalities : [raid1]

md0 : active raid1 sda1[2] sdb1[3]

524224 blocks super 1.0 [2/2] [UU]
md2 : active raid1 sdb3[3] sda3[2]

972009280 blocks super 1.1 [2/1] [_U]

[>....................]  recovery =  0.0% (295168/972009280) finish=109.7min speed=147584K/sec

bitmap: 5/8 pages [20KB], 65536KB chunk
md1 : active raid1 sdb2[3] sda2[2]

4093888 blocks super 1.1 [2/2] [UU] 
We wait until the next day when it ends in sync.
Day 2. We do the same with the other hard drive,  /dev/sda3  but first we restart!
Warning After you change your hard drive and increase partitions you may have problems with grub because it changes the hardships.
I will put a short video with my steps în other post !


@luciancovaci

If you liked it

Upvote and Follow!

Created on 20170918 at  10:52 EET