Rebuild new disk array

Hi,
maybe this question can be easy to answer, although I don't have too much experience with replacing array disks.

The provider replaced one failed disk (of two disk in array). Now the server boots and works only with the second disk. However, the array was not rebuilt after boot as I expected.

I have read quite tutorials but I'm not sure what to do.
I'm not sure if I should put attention to the warning on GPT because some relevance in the operation to mirror the disk.

The new disk is /sda, and the working disk is /sdb :

Code:

# lsblk

NAME    MAJ:MIN RM    SIZE RO TYPE  MOUNTPOINT
sda       8:0    0    1.8T  0 disk
sdb       8:16   0    1.8T  0 disk
+-sdb1    8:17   0 1004.5K  0 part
+-sdb2    8:18   0    255M  0 part
¦ +-md2   9:2    0    255M  0 raid1 /boot
+-sdb3    8:19   0   97.7G  0 part
¦ +-md3   9:3    0   97.7G  0 raid1 /
+-sdb4    8:20   0    1.7T  0 part
¦ +-md4   9:4    0    1.7T  0 raid1 /home
+-sdb5    8:21   0    511M  0 part  [SWAP]
loop0     7:0    0     10M  0 loop

Code:

# cat /proc/mdstat
Personalities : [linear] [raid0] [raid1] [raid10] [raid6] [raid5] [raid4] [multipath] [faulty]
md2 : active raid1 sdb2[1]
      261056 blocks [2/1] [_U]
  
md3 : active raid1 sdb3[1]
      102398912 blocks [2/1] [_U]
  
md4 : active raid1 sdb4[1]
      1850323904 blocks [2/1] [_U]
      bitmap: 14/14 pages [56KB], 65536KB chunk

unused devices: <none>

Code:

# fdisk -l

Disk /dev/loop0: 10 MB, 10485760 bytes
255 heads, 63 sectors/track, 1 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x00000000


Disk /dev/sda: 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 / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x00000000


WARNING: GPT (GUID Partition Table) detected on '/dev/sdb'! The util fdisk doesn't support GPT. Use GNU Parted.


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      243202  1953514583+  ee  GPT
Partition 1 does not start on physical sector boundary.

Disk /dev/md4: 1894.7 GB, 1894731677696 bytes
2 heads, 4 sectors/track, 462580976 cylinders
Units = cylinders of 8 * 512 = 4096 bytes
Sector size (logical/physical): 512 bytes / 4096 bytes
I/O size (minimum/optimal): 4096 bytes / 4096 bytes
Disk identifier: 0x00000000


Disk /dev/md3: 104.9 GB, 104856485888 bytes
2 heads, 4 sectors/track, 25599728 cylinders
Units = cylinders of 8 * 512 = 4096 bytes
Sector size (logical/physical): 512 bytes / 4096 bytes
I/O size (minimum/optimal): 4096 bytes / 4096 bytes
Disk identifier: 0x00000000


Disk /dev/md2: 267 MB, 267321344 bytes
2 heads, 4 sectors/track, 65264 cylinders
Units = cylinders of 8 * 512 = 4096 bytes
Sector size (logical/physical): 512 bytes / 4096 bytes
I/O size (minimum/optimal): 4096 bytes / 4096 bytes
Disk identifier: 0x00000000

After reading some tutorials, I think in this procedure:

copy the boot sector:

Code:

# sfdisk -d /dev/sdb | sfdisk /dev/sda

reassign:

Code:

# mdadm /dev/md2 -a /dev/sda2
# mdadm /dev/md3 -a /dev/sda3
# mdadm /dev/md4 -a /dev/sda4

make the device map

Code:

# grub-mkdevicemap -n

and then wait the resync process

Code:

# watch cat /proc/mdstat

and that's all.

Do you think it will work without error or there is something I miss?

This is a server in production and without possibility of previous backup. I'm afraid if my sequence can cause a boot failure or even damage the disk. I cannot try or do tests.

I would be really grateful for any thought.

 

nobody can help?. I know this is no directly related with ISPC although later I plain to install on that

 

thanks till.
although my doubt was specially with the warning
"WARNING: GPT (GUID Partition Table) detected on '/dev/sdb'! The util fdisk doesn't support GPT. Use GNU Parted."

I'm not sure if I should ignore it or not

thx anyway

 

oh, good Then i will try it

thx!