I started configuring an HP ProLiant N54L microserver today and when I got to the raid array part I noticed that some of the tutorials for debian are not quite working, so I made this step by step tutorial for the others having problems out there.
Creating the RAID 1 Array Using mdadm
root@somehost # apt-get install mdadm
Step 2: Choose your RAID type
The server I`m using supports RAID0 and RAID1, but I was looking for mirroring redundancy and fault tolerance so I chose RAID1…
The following table shows some of the main differences between RAID0 and RAID1 in a nutshell:
| RAID0 | RAID1 | |
| Mirroring, redundancy and fault tolerance | No | Yes |
| Striping | Yes, data is split evenly across all dikcs in the array | No, data is fully stored on each disk |
| Performance | Faster write speeds compared to RAID1 | Same performance as RAID0 but write is slower |
| Applications | Where speed is important | Where data loss is unacceptable |
Step 3: Find your hdds
root@somehost # fdisk -l
The output should be something similar to:
Disk /dev/sda: 250.1 GB, 250059350016 bytes 255 heads, 63 sectors/track, 30401 cylinders, total 488397168 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 identifier: 0x000e7ea8 Device Boot Start End Blocks Id System /dev/sda1 * 2048 499711 248832 83 Linux /dev/sda2 501758 488396799 243947521 5 Extended /dev/sda5 501760 488396799 243947520 8e Linux LVM Disk /dev/sdb: 1000.2 GB, 1000204886016 bytes 255 heads, 63 sectors/track, 121601 cylinders, total 1953525168 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 Disk identifier: 0x00000000 Device Boot Start End Blocks Id System /dev/sdb1 1 1953525167 976762583+ ee GPT Disk /dev/sdc: 1000.2 GB, 1000204886016 bytes 255 heads, 63 sectors/track, 121601 cylinders, total 1953525168 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 Disk identifier: 0x00000000 Device Boot Start End Blocks Id System /dev/sdc1 1 1953525167 976762583+ ee GPT
The ones I’m interested in are /dev/sdb1 and /dev/sdc1
Step 4: Edit /etc/mdadm/mdadm.conf
root@somehost # vi /etc/mdadm/mdadm.conf
Add the following lines at the end of the file:
DEVICE /dev/sd[bc]1 ARRAY /dev/md0 devices=/dev/sdb1,/dev/sdc1
*Note change sdb1 and sdc1 with your drives
Step 5: Create the RAID array
root@somehost # mdadm -C /dev/md0 –level=raid1 -raid-devices=2 /dev/sdb1 /dev/sdc1
After entering the command mdadm will ask if it should continue creating the array, you should type “Yes”
Continue creating array? yes mdadm: array /dev/md0 started.
Step 6: Query your RAID for status information
root@somehost # mdadm --detail /dev/md0
And the output should be something along the lines of:
/dev/md0: Version : 1.2 Creation Time : Thu Feb 20 13:20:02 2014 Raid Level : raid1 Array Size : 976629568 (931.39 GiB 1000.07 GB) Used Dev Size : 976629568 (931.39 GiB 1000.07 GB) Raid Devices : 2 Total Devices : 2 Persistence : Superblock is persistent Update Time : Thu Feb 20 13:20:02 2014 State : clean, resyncing (PENDING) Active Devices : 2 Working Devices : 2 Failed Devices : 0 Spare Devices : 0 Name : hpproliant:0 (local to host hpproliant) UUID : 9c9c5ca2:a4b26264:5d73d487:373aa79c Events : 0 Number Major Minor RaidDevice State 0 8 17 0 active sync /dev/sdb1 1 8 33 1 active sync /dev/sdc1
Step 7: This is probably os specific but in my case the array didn’t start rebuilding automatically so I had to input the following command to get it started
[sourcecode]root@somehost# mdadm –readwrite /dev/md0[/sourcecode]
You can monitor the process with:
root@somehost# watch cat /proc/mdstat
Every 2.0s: cat /proc/mdstat Thu Feb 20 14:11:09 2014 Personalities : [raid1] md0 : active raid1 sdc1[1] sdb1[0] 976629568 blocks super 1.2 [2/2] [UU] [==========>..........] resync = 51.0% (498891200/976629568) finish=48.7min speed=163438K/sec unused devices: <none>
Once this is done you can check the output of the “mdadm –detail /dev/md0” command again and this time it will be something like:
/dev/md0: Version : 1.2 Creation Time : Thu Feb 20 13:20:02 2014 Raid Level : raid1 Array Size : 976629568 (931.39 GiB 1000.07 GB) Used Dev Size : 976629568 (931.39 GiB 1000.07 GB) Raid Devices : 2 Total Devices : 2 Persistence : Superblock is persistent Update Time : Thu Feb 20 15:14:19 2014 State : clean Active Devices : 2 Working Devices : 2 Failed Devices : 0 Spare Devices : 0 Name : hpproliant:0 (local to host hpproliant) UUID : 9c9c5ca2:a4b26264:5d73d487:373aa79c Events : 17 Number Major Minor RaidDevice State 0 8 17 0 active sync /dev/sdb1 1 8 33 1 active sync /dev/sdc1
Step 8: Format the new RAID array
root@somehost# mkfs.ext4 /dev/md0
mke2fs 1.42.5 (29-Jul-2012) Filesystem label= OS type: Linux Block size=4096 (log=2) Fragment size=4096 (log=2) Stride=0 blocks, Stripe width=0 blocks 61046784 inodes, 244157392 blocks 12207869 blocks (5.00%) reserved for the super user First data block=0 Maximum filesystem blocks=4294967296 7452 block groups 32768 blocks per group, 32768 fragments per group 8192 inodes per group Superblock backups stored on blocks: 32768, 98304, 163840, 229376, 294912, 819200, 884736, 1605632, 2654208, 4096000, 7962624, 11239424, 20480000, 23887872, 71663616, 78675968, 102400000, 214990848 Allocating group tables: done Writing inode tables: done Creating journal (32768 blocks): done Writing superblocks and filesystem accounting information: done
Step 9: Create a mount point for your new RAID and make it automount
Create a directory for your mount point, it doesn’t really matter where it is and change the permissions to 775.
root@somehost# mkdir /home/raid1_md0 root@somehost# chmod 775 /home/raid1_md0
Find the UUID of your RAID array
root@somehost# blkid | grep md0
/dev/md0: UUID="a0fa881f-d12f-47d7-971a-e711a71be7b7" TYPE="ext4"
Now open fstab
root@somehost# vi /etc/fstab
And add the following line at the end of the file
UUID=a0fa881f-d12f-47d7-971a-e711a71be7b7 /home/raid1_md0 ext4 defaults 0
*Note: Of course change the UUID and the folder path to yours
You can mount the array by typing “mount -a”
And if everything went fine you`ll probably see it in the output of “df”
root@somehost# df Filesystem 1K-blocks Used Available Use% Mounted on rootfs 329233 147561 164674 48% / udev 10240 0 10240 0% /dev tmpfs 192948 400 192548 1% /run /dev/mapper/hpproliant-root 329233 147561 164674 48% / tmpfs 5120 0 5120 0% /run/lock tmpfs 385880 0 385880 0% /run/shm /dev/sda1 233191 18346 202404 9% /boot /dev/mapper/hpproliant-home 224001588 191740 212431160 1% /home /dev/mapper/hpproliant-tmp 376807 10257 347094 3% /tmp /dev/mapper/hpproliant-usr 8647944 779672 7428976 10% /usr /dev/mapper/hpproliant-var 2882592 284564 2451596 11% /var /dev/md0 961303696 204436 912267784 1% /home/raid1_md0
Reboot the machine and enjoy 🙂