yet another software RAID debian

Notes taken while I was converting an 1 hard drive system to a 4 hard drives system with software RAID Arrays.

  • 2 x 1TB hard drives contributing one partition each to a software RAID 1 array and contributing one swap partition each to the system.
  • 2 x 3TB hard drives contributing two partitions each to software RAID 1 Arrays.


The system:
# cat /etc/issue /etc/debian_version
Debian GNU/Linux 6.0 \n \l

6.0.7
# uname -r
2.6.32-5-amd64


Install the Multiple Devices MD --Linux Software RAID Array-- Manager
# apt-get install mdadm


Check out the disk used by the System.
# fdisk -l

Disk /dev/sda: 1000.2 GB, 1000204886016 bytes
255 heads, 63 sectors/track, 121601 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: 0x000a8440

   Device Boot      Start         End      Blocks   Id  System
/dev/sda1   *           1      121133   972993536   83  Linux
/dev/sda2          121133      121602     3766273    5  Extended
/dev/sda5          121133      121602     3766272   82  Linux swap / Solaris


OK, shut it down and add the other ~ 1TB disk

Look at the disks
# sfdisk -l

Disk /dev/sda: 121601 cylinders, 255 heads, 63 sectors/track
Warning: extended partition does not start at a cylinder boundary.
DOS and Linux will interpret the contents differently.
Units = cylinders of 8225280 bytes, blocks of 1024 bytes, counting from 0

   Device Boot Start     End   #cyls    #blocks   Id  System
/dev/sda1   *      0+ 121132- 121133- 972993536   83  Linux
/dev/sda2     121132+ 121601-    469-   3766273    5  Extended
/dev/sda3          0       -       0          0    0  Empty
/dev/sda4          0       -       0          0    0  Empty
/dev/sda5     121132+ 121601-    469-   3766272   82  Linux swap / Solaris

Disk /dev/sdb: 121601 cylinders, 255 heads, 63 sectors/track

sfdisk: ERROR: sector 0 does not have an msdos signature
 /dev/sdb: unrecognized partition table type
No partitions found


Copy the partition table of /dev/sda to /dev/sdb
# sfdisk -d /dev/sda | sfdisk --force /dev/sdb


List all logical drives on all hard drives
# sfdisk -l

Disk /dev/sda: 121601 cylinders, 255 heads, 63 sectors/track
Warning: extended partition does not start at a cylinder boundary.
DOS and Linux will interpret the contents differently.
Units = cylinders of 8225280 bytes, blocks of 1024 bytes, counting from 0

   Device Boot Start     End   #cyls    #blocks   Id  System
/dev/sda1   *      0+ 121132- 121133- 972993536   83  Linux
/dev/sda2     121132+ 121601-    469-   3766273    5  Extended
/dev/sda3          0       -       0          0    0  Empty
/dev/sda4          0       -       0          0    0  Empty
/dev/sda5     121132+ 121601-    469-   3766272   82  Linux swap / Solaris

Disk /dev/sdb: 121601 cylinders, 255 heads, 63 sectors/track
Warning: extended partition does not start at a cylinder boundary.
DOS and Linux will interpret the contents differently.
Units = cylinders of 8225280 bytes, blocks of 1024 bytes, counting from 0

   Device Boot Start     End   #cyls    #blocks   Id  System
/dev/sdb1   *      0+ 121132- 121133- 972993536   83  Linux
/dev/sdb2     121132+ 121601-    469-   3766273    5  Extended
/dev/sdb3          0       -       0          0    0  Empty
/dev/sdb4          0       -       0          0    0  Empty
/dev/sdb5     121132+ 121601-    469-   3766272   82  Linux swap / Solaris


Set /dev/sdb1 0x ID to 0xfd ( Linux RAID Auto )
# sfdisk --change-id /dev/sdb 1 fd


# sfdisk -l /dev/sdb

Disk /dev/sdb: 121601 cylinders, 255 heads, 63 sectors/track
Warning: extended partition does not start at a cylinder boundary.
DOS and Linux will interpret the contents differently.
Units = cylinders of 8225280 bytes, blocks of 1024 bytes, counting from 0

   Device Boot Start     End   #cyls    #blocks   Id  System
/dev/sdb1   *      0+ 121132- 121133- 972993536   fd  Linux raid autodetect
/dev/sdb2     121132+ 121601-    469-   3766273    5  Extended
/dev/sdb3          0       -       0          0    0  Empty
/dev/sdb4          0       -       0          0    0  Empty
/dev/sdb5     121132+ 121601-    469-   3766272   82  Linux swap / Solaris


Overwrite with zeros MD superblocks --remains of RAID Arrays-- if any.
# mdadm --zero-superblock --force /dev/sdb1


Create a RAID 1 Array of 2 logical disks using the v0.90 superblock format
# mdadm --create /dev/md0 --level=1 --metadata=0 --raid-disks=2 missing  /dev/sdb1
mdadm: array /dev/md0 started.
"The version-0.90 superblock limits the number of component devices within an array to 28, and limits each component device to a maximum size of 2TB on kernel version <3.1 and 4TB on kernel version >=3.1." The version-0.90 Superblock Format

Look at proc
# cat /proc/mdstat 
Personalities : [raid1] 
md0 : active raid1 sdb1[1]
      972993472 blocks [2/1] [_U]
      
unused devices: 


Create an ext3 file-system on the Multiple Devices MD device /dev/md0
# mkfs.ext3 -v -m .1 -b 4096 -E stride=32,stripe-width=64 /dev/md0
with stripe-width=64 , it should not matter in RAID 1 Arrays.
Options explained:
     The first command makes a ext3 filesystem
     -v verbose
     -m .1 leave .1% of disk to root 
     -b 4096 block size of 4kb (recommended above for large-file systems)
     -E stride=32,stripe-width=64 see below calculation
RAID wiki

Backup mdadm.conf
# cp /etc/mdadm/mdadm.conf /etc/mdadm/mdadm.conf.0
Delete ARRAY definitions from /etc/mdadm/mdadm.conf
# grep -v ARRAY /etc/mdadm/mdadm.conf >> /etc/mdadm/mdadm.conf
Update /etc/mdadm/mdadm.conf
# mdadm --examine --scan >> /etc/mdadm/mdadm.conf


Mount md0
# mkdir /mnt/md0
# mount /dev/md0 /mnt/md0/


Save /etc/fstab for historical reasons
# cp /etc/fstab /etc/fstab.0
Remove or comment out lines starting with UUID or /dev/sd* from /etc/fstab
and make /etc/fstab look like the following.
# grep -v "#" /etc/fstab
proc            /proc           proc    defaults        0       0
/dev/md0         /              ext3    errors=remount-ro 0       1
/dev/sda5 swap  swap defaults,pri=1   0  0
/dev/sdb5 swap  swap defaults,pri=1   0  0
Swapping on RAID

Configure the bootloader --Grub2
# cp /etc/grub.d/40_custom /etc/grub.d/08_raid1
# vi /etc/grub.d/08_raid1
Here is my /etc/grub.d/08_raid1 :
#!/bin/sh
exec tail -n +3 $0
# This file provides an easy way to add custom menu entries.  Simply type the
# menu entries you want to add after this comment.  Be careful not to change
# the 'exec tail' line above.
menuentry 'Debian GNU/Linux, with Linux 2.6.32-5-amd64 raid1' --class debian --class gnu-linux --class gnu --class os {
        insmod raid
        insmod mdraid
        insmod part_msdos
        insmod ext2
        set root='(md0)'
        echo    'Loading Linux 2.6.32-5-amd64 ...'
        linux   /boot/vmlinuz-2.6.32-5-amd64 root=/dev/md0 ro  quiet
        echo    'Loading initial ramdisk ...'
        initrd  /boot/initrd.img-2.6.32-5-amd64
}


Un-comment or add
GRUB_DISABLE_LINUX_UUID=true
at /etc/default/grub

Replace /dev/sda with /dev/md0 in /etc/mtab
and delete the line showing /dev/md0 mount on /mnt/md0

Update grub.cfg
# grub-mkconfig -o /boot/grub/grub.cfg 


Update the initramfs image
# update-initramfs -u


Copy the System to /dev/md0
# cp -dpRx / /mnt/md0


Install grub on all drives.
# grub-install /dev/sdb
# grub-install /dev/sda



Cross your fingers and reboot
# shutdown -r now


OK, the system came up as expected.
Check proc
# cat /proc/mdstat 
Personalities : [raid1] 
md0 : active raid1 sdb1[1]
      972993472 blocks [2/1] [_U]
      
unused devices: 


Set /dev/sda1 0x ID to 0xfd ( Linux RAID Auto )
# sfdisk --change-id /dev/sda 1 fd


List all partitions on all drives
# sfdisk -l

Disk /dev/sda: 121601 cylinders, 255 heads, 63 sectors/track
Warning: extended partition does not start at a cylinder boundary.
DOS and Linux will interpret the contents differently.
Units = cylinders of 8225280 bytes, blocks of 1024 bytes, counting from 0

   Device Boot Start     End   #cyls    #blocks   Id  System
/dev/sda1   *      0+ 121132- 121133- 972993536   fd  Linux raid autodetect
/dev/sda2     121132+ 121601-    469-   3766273    5  Extended
/dev/sda3          0       -       0          0    0  Empty
/dev/sda4          0       -       0          0    0  Empty
/dev/sda5     121132+ 121601-    469-   3766272   82  Linux swap / Solaris

Disk /dev/sdb: 121601 cylinders, 255 heads, 63 sectors/track
Warning: extended partition does not start at a cylinder boundary.
DOS and Linux will interpret the contents differently.
Units = cylinders of 8225280 bytes, blocks of 1024 bytes, counting from 0

   Device Boot Start     End   #cyls    #blocks   Id  System
/dev/sdb1   *      0+ 121132- 121133- 972993536   fd  Linux raid autodetect
/dev/sdb2     121132+ 121601-    469-   3766273    5  Extended
/dev/sdb3          0       -       0          0    0  Empty
/dev/sdb4          0       -       0          0    0  Empty
/dev/sdb5     121132+ 121601-    469-   3766272   82  Linux swap / Solaris

Disk /dev/md0: 243248368 cylinders, 2 heads, 4 sectors/track

sfdisk: ERROR: sector 0 does not have an msdos signature
 /dev/md0: unrecognized partition table type
No partitions found



Add /dev/sda1 to the RAID 1 md0
# mdadm --add /dev/md0 /dev/sda1
mdadm: added /dev/sda1


Check proc mdstat
# cat /proc/mdstat 
Personalities : [raid1] 
md0 : active raid1 sda1[2] sdb1[1]
      972993472 blocks [2/1] [_U]
      [>....................]  recovery =  0.4% (4773696/972993472) finish=144.5min speed=111602K/sec
      
unused devices: 


Check load
22:53:31 up 20 min,  1 user,  load average: 0.66, 0.19, 0.06
Not (very) bad ;)

Wait for the raid array to sync.

root@bob:~# cat /proc/mdstat 
Personalities : [raid1] 
md0 : active raid1 sda1[2] sdb1[1]
      972993472 blocks [2/1] [_U]
      [===========>.........]  recovery = 56.1% (546131776/972993472) finish=74.2min speed=95857K/sec
      
unused devices: 


Done.
# cat /proc/mdstat 
Personalities : [raid1] 
md0 : active raid1 sda1[0] sdb1[1]
      972993472 blocks [2/2] [UU]
      
unused devices: 


Test! What if I take off /dev/sdb ?
# shutdown -h now
take of /dev/sdb and boot

It came up fine :) , check proc
# cat /proc/mdstat 
Personalities : [raid1] 
md0 : active raid1 sda1[0]
      972993472 blocks [2/1] [U_]
      
unused devices: 


(

Yet another not-very-cheap way for a technician
to hide 'some' tracks (I think)
in a dedicated server farm.

  • shutdown the system
  • take off drive a
  • do crap
  • shutdown the system, take off drive b , put in drive a , boot
  • shutdown the system, put in drive b, and let them sync

)

Back to business ...
  • shutdown the system
  • put in sdb
  • and boot


It came up fine, check proc
# cat /proc/mdstat 
Personalities : [raid1] 
md0 : active raid1 sda1[0]
      972993472 blocks [2/1] [U_]
      
unused devices: 
Add /dev/sdb to the RAID array
# mdadm --add /dev/md0 /dev/sdb1
Check proc
# cat /proc/mdstat 
Personalities : [raid1] 
md0 : active raid1 sdb1[2] sda1[0]
      972993472 blocks [2/1] [U_]
      [>....................]  recovery =  3.6% (35851584/972993472) finish=145.8min speed=107124K/sec
      
unused devices: 


OK, Let 's create the "DATA" arrays.
  • shutdown the system
  • put in the 3TB hard drives
  • Set on BIOS to boot only from /dev/sda and /dev/sdb
  • boot


OK the system came up.
Check out proc
# cat /proc/mdstat 
Personalities : [raid1] 
md0 : active raid1 sda1[0] sdb1[2]
      972993472 blocks [2/1] [U_]
      [>....................]  recovery =  0.0% (449280/972993472) finish=15694.6min speed=1032K/sec
      
unused devices: 


List all logical and physical disks
# sfdisk -l

Disk /dev/sda: 121601 cylinders, 255 heads, 63 sectors/track
Warning: extended partition does not start at a cylinder boundary.
DOS and Linux will interpret the contents differently.
Units = cylinders of 8225280 bytes, blocks of 1024 bytes, counting from 0

   Device Boot Start     End   #cyls    #blocks   Id  System
/dev/sda1   *      0+ 121132- 121133- 972993536   fd  Linux raid autodetect
/dev/sda2     121132+ 121601-    469-   3766273    5  Extended
/dev/sda3          0       -       0          0    0  Empty
/dev/sda4          0       -       0          0    0  Empty
/dev/sda5     121132+ 121601-    469-   3766272   82  Linux swap / Solaris

Disk /dev/sdb: 121601 cylinders, 255 heads, 63 sectors/track
Warning: extended partition does not start at a cylinder boundary.
DOS and Linux will interpret the contents differently.
Units = cylinders of 8225280 bytes, blocks of 1024 bytes, counting from 0

   Device Boot Start     End   #cyls    #blocks   Id  System
/dev/sdb1   *      0+ 121132- 121133- 972993536   fd  Linux raid autodetect
/dev/sdb2     121132+ 121601-    469-   3766273    5  Extended
/dev/sdb3          0       -       0          0    0  Empty
/dev/sdb4          0       -       0          0    0  Empty
/dev/sdb5     121132+ 121601-    469-   3766272   82  Linux swap / Solaris

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


Disk /dev/sdd: 364801 cylinders, 255 heads, 63 sectors/track
Units = cylinders of 8225280 bytes, blocks of 1024 bytes, counting from 0

   Device Boot Start     End   #cyls    #blocks   Id  System
/dev/sdd1          0+ 267349- 267350- 2147483647+  ee  GPT
  start: (c,h,s) expected (0,0,2) found (0,0,1)
/dev/sdd2          0       -       0          0    0  Empty
/dev/sdd3          0       -       0          0    0  Empty
/dev/sdd4          0       -       0          0    0  Empty

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


Disk /dev/sdc: 364801 cylinders, 255 heads, 63 sectors/track
Units = cylinders of 8225280 bytes, blocks of 1024 bytes, counting from 0

   Device Boot Start     End   #cyls    #blocks   Id  System
/dev/sdc1          0+ 267349- 267350- 2147483647+  ee  GPT
  start: (c,h,s) expected (0,0,2) found (0,0,1)
/dev/sdc2          0       -       0          0    0  Empty
/dev/sdc3          0       -       0          0    0  Empty
/dev/sdc4          0       -       0          0    0  Empty

Disk /dev/md0: 243248368 cylinders, 2 heads, 4 sectors/track

sfdisk: ERROR: sector 0 does not have an msdos signature
 /dev/md0: unrecognized partition table type
No partitions found


Partition the /dev/sdc hard drive
# parted /dev/sdc
GNU Parted 2.3
Using /dev/sdc
Welcome to GNU Parted! Type 'help' to view a list of commands.
(parted) mklabel gpt
Warning: The existing disk label on /dev/sdc will be destroyed and all data on this disk will be lost. Do you want to continue?
Yes/No? yes                                                               
(parted) mkpart data00 0GB 1501GB                                         
(parted) mkpart data01 1502BG 3001GB
Warning: You requested a partition from 1024B to 3001GB.                  
The closest location we can manage is 17.4kB to 1048kB.
Is this still acceptable to you?
Yes/No? no                                                                
(parted) quit                                                             
Information: You may need to update /etc/fstab.                           
  


Now, I could use parted again to partition /dev/sdd.
However, I really want to try to clone GPT disks with gdisk --GPT fdisk.
For debian GPT fdisk, currently is found in sid.

Install gdisk
# echo "deb http://ftp.it.debian.org/debian sid main" >> /etc/apt/sources.list
# apt-get update
# apt-get install gdiskgdisk
GPT fdisk (gdisk) version 0.8.5

Type device filename, or press  to exit: 
#
Not bad, at this moment the latest GPT fdisk version is 0.8.6.

Comment out the ftp.it.debian.org repository, add a squeeze repository and
# apt-get update


sgdisk is part of GPT fdisk --gdisk.
Copy the partition scheme of sdc to sdd and change the GUID on /dev/sdd.
# sgdisk -R=/dev/sdd /dev/sdc
The operation has completed successfully.
#  sgdisk -G /dev/sdd
The operation has completed successfully.


excerpt from the sgdisk man page.
-R, --replicate=second_device_filename
              Replicate the main device's partition table on the specified second device.  Note that the replicated partition table is
              an  exact copy, including all GUIDs; if the device should have its own unique GUIDs, you should use the -G option on the
              new disk.



List all logical and physical disks.
# parted -l
Model: ATA WDC WD1002FAEX-0 (scsi)
Disk /dev/sda: 1000GB
Sector size (logical/physical): 512B/512B
Partition Table: msdos

Number  Start   End     Size    Type      File system     Flags
 1      1049kB  996GB   996GB   primary   ext3            boot, raid
 2      996GB   1000GB  3857MB  extended
 5      996GB   1000GB  3857MB  logical   linux-swap(v1)


Model: ATA WDC WD1002FAEX-0 (scsi)
Disk /dev/sdb: 1000GB
Sector size (logical/physical): 512B/512B
Partition Table: msdos

Number  Start   End     Size    Type      File system  Flags
 1      1049kB  996GB   996GB   primary   ext3         boot, raid
 2      996GB   1000GB  3857MB  extended
 5      996GB   1000GB  3857MB  logical


Model: ATA WDC WD30EFRX-68A (scsi)
Disk /dev/sdc: 3001GB
Sector size (logical/physical): 512B/4096B
Partition Table: gpt

Number  Start   End     Size    File system  Name    Flags
 1      1049kB  1501GB  1501GB               data00
 2      1502GB  3001GB  1499GB               data01


Model: ATA WDC WD30EFRX-68A (scsi)
Disk /dev/sdd: 3001GB
Sector size (logical/physical): 512B/4096B
Partition Table: gpt

Number  Start   End     Size    File system  Name    Flags
 1      1049kB  1501GB  1501GB               data00
 2      1502GB  3001GB  1499GB               data01


Model: Linux Software RAID Array (md)
Disk /dev/md0: 996GB
Sector size (logical/physical): 512B/512B
Partition Table: loop

Number  Start  End    Size   File system  Flags
 1      0.00B  996GB  996GB  ext3



Set the raid flag to true on all logical partitions of /dev/sdc.
# parted /dev/sdc
GNU Parted 2.3
Using /dev/sdc
Welcome to GNU Parted! Type 'help' to view a list of commands.
(parted) print                                                            
Model: ATA WDC WD30EFRX-68A (scsi)
Disk /dev/sdc: 3001GB
Sector size (logical/physical): 512B/4096B
Partition Table: gpt

Number  Start   End     Size    File system  Name    Flags
 1      1049kB  1501GB  1501GB               data00
 2      1502GB  3001GB  1499GB               data01

(parted) set 1 raid on                                                    
(parted) set 2 raid on
(parted) print
Model: ATA WDC WD30EFRX-68A (scsi)
Disk /dev/sdc: 3001GB
Sector size (logical/physical): 512B/4096B
Partition Table: gpt

Number  Start   End     Size    File system  Name    Flags
 1      1049kB  1501GB  1501GB               data00  raid
 2      1502GB  3001GB  1499GB               data01  raid

(parted) quit                                                             
Information: You may need to update /etc/fstab.    


Set the raid flag to true on all logical partition of /dev/sdd.
# parted /dev/sdd
GNU Parted 2.3
Using /dev/sdd
Welcome to GNU Parted! Type 'help' to view a list of commands.
(parted) print                                                            
Model: ATA WDC WD30EFRX-68A (scsi)
Disk /dev/sdd: 3001GB
Sector size (logical/physical): 512B/4096B
Partition Table: gpt

Number  Start   End     Size    File system  Name    Flags
 1      1049kB  1501GB  1501GB               data00
 2      1502GB  3001GB  1499GB               data01

(parted) set 1 raid on
(parted) set 2 raid on                                                    
(parted) print                                                            
Model: ATA WDC WD30EFRX-68A (scsi)
Disk /dev/sdd: 3001GB
Sector size (logical/physical): 512B/4096B
Partition Table: gpt

Number  Start   End     Size    File system  Name    Flags
 1      1049kB  1501GB  1501GB               data00  raid
 2      1502GB  3001GB  1499GB               data01  raid

(parted) quit                                                             
Information: You may need to update /etc/fstab.


Look the partitions in proc
# cat /proc/partitions 
major minor  #blocks  name

   8        0  976762584 sda
   8        1  972993536 sda1
   8        2          1 sda2
   8        5    3766272 sda5
   8       16  976762584 sdb
   8       17  972993536 sdb1
   8       18          1 sdb2
   8       21    3766272 sdb5
   8       48 2930266584 sdd
   8       49 1465819136 sdd1
   8       50 1463469056 sdd2
   8       32 2930266584 sdc
   8       33 1465819136 sdc1
   8       34 1463469056 sdc2
   9        0  972993472 md0



Create the md1 data00 raid 1 Array.
# mdadm --create /dev/md1 --level=1 --metadata=0 --raid-disks=2 /dev/sdc1 /dev/sdd1
mdadm: array /dev/md1 started.


Format /dev/md1
# mkfs.ext3 -v -m .1 -b 4096 -E stride=32,stripe-width=64 /dev/md1


Create the md2 data01 raid 1 Array
#  mdadm --create /dev/md2 --level=1 --metadata=0 --raid-disks=2 /dev/sdc2 /dev/sdd2
mdadm: array /dev/md2 started.


Format /dev/md2
# mkfs.ext3 -v -m .1 -b 4096 -E stride=32,stripe-width=64 /dev/md2


Update mdadmn.conf
# mdadm --examine --scan >> /etc/mdadm/mdadm.conf
# vi /etc/mdadm/mdadm.conf
delete multiple ARRAY definitions

Create mount points and update /etc/fstab
# mkdir /data00
# mkdir /data01
# vi /etc/fstab
This is how my /etc/fstab looks like
# grep -v "#" /etc/fstab
proc            /proc           proc    defaults        0       0
/dev/md0         /              ext3    errors=remount-ro 0       1
/dev/sda5 swap  swap defaults,pri=1   0  0
/dev/sdb5 swap  swap defaults,pri=1   0  0
/dev/md1         /data00        ext3    errors=remount-ro 0       1
/dev/md2         /data01        ext3    errors=remount-ro 0       1


Look at /proc/mdstat
# cat /proc/mdstat 
Personalities : [raid1] 
md2 : active raid1 sdd2[1] sdc2[0]
      1463468992 blocks [2/2] [UU]
       resync=DELAYED
      
md1 : active raid1 sdd1[1] sdc1[0]
      1465819072 blocks [2/2] [UU]
      [=>...................]  resync =  6.8% (100567936/1465819072) finish=172.6min speed=131767K/sec
      
md0 : active raid1 sda1[0] sdb1[1]
      972993472 blocks [2/2] [UU]
      
unused devices: 



# reboot


The system came up fine
Loot at what is mounted and filesystem usage.
# df -h
Filesystem            Size  Used Avail Use% Mounted on
/dev/md0              914G  1.6G  911G   1% /
tmpfs                 943M     0  943M   0% /lib/init/rw
udev                  936M  168K  936M   1% /dev
tmpfs                 943M     0  943M   0% /dev/shm
/dev/md1              1.4T  198M  1.4T   1% /data00
/dev/md2              1.4T  198M  1.4T   1% /data01


Look at mdstat
# cat /proc/mdstat 
Personalities : [raid1] 
md2 : active raid1 sdc2[0] sdd2[1]
      1463468992 blocks [2/2] [UU]
       resync=DELAYED
      
md1 : active raid1 sdc1[0] sdd1[1]
      1465819072 blocks [2/2] [UU]
      [=>...................]  resync =  8.6% (127094592/1465819072) finish=168.6min speed=132290K/sec
      
md0 : active raid1 sda1[0] sdb1[1]
      972993472 blocks [2/2] [UU]
      
unused devices: 



Look the load
# w
 21:24:43 up 1 min,  1 user,  load average: 2.17, 0.75, 0.27
ouch! I 'll keep you posted on that.

Done!



Yet another Software RAID on Debian GNU Linux