patrik.cqure.net

I recieved my bubba two storage solution from Excito today! I must say that I was both surprised and impressed once I unwrapped and pluged it in to my network. It was both smaller and quiter than I expected!

I also purchased an additional 1TB eSata drive, also from Excito, which looks almost the same as the server. Knowing from their specs that the device did not yet support raid-1 I was nevertheless hoping to get this running with the additional disk I bought. So far I have synced 39.2% of the new raid array I created and things are looking very promising. For anyone intrested, these are the steps I took:

First of all I setup a new account through which I could access the server through SSH. I then connected to the system over SSH to look at the partition table. Fortunately the layout was quite good and required only little work to adapt it for mirroring. The bubba two server I bought came with a 1TB disk partitioned like this:

/dev/sda1          0+   1216    1217-   9775521   83  Linux
/dev/sda2       1217  121456  120240  965827800   8E  Linux LVM
/dev/sda3     121457  121600     144    1156680   82  Linux swap / Solaris

My concern was to mirror the “storage” partition (sda2) where I will be keeping my data. This partition was currently mounted as /home which was in use as it contained my home directory. So in order to start building the RAID array I had to do some small preparations. All of the commands should be executed as root.

To be able to unmount the partition I first created a new “home” directory

mkdir /home2

I then copied all of the contents from /home to /home2

cp -a /home/* /home2/

With the home contents in the new directory I opened the passwd file and changed my home-directory from home to home2

 nano -w /etc/passwd

In order to minimize the chance of screw-up I opened a new terminal window after saving the passwd file to verify that I could still SSH to the box. Once this was done I unmounted the old /home partition, which should no longer be busy.

umount /home

Now we’re ready to start removing volume-groups, logical volumes and other disk mappings I did this by executing the following commands:

lvremove bubba/storage
vgremove bubba
pvremove /dev/sda2

Once this was done I needed to change the partition type for the second partition from LVM to RAID. I did this by starting cfdisk, selecting the second partition and then chose types. The type needs to be changed from 8E to FD. After this I simply copied the partition table from /dev/sda to /dev/sdb using sfdisk using:

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

With the partitions in place I created the raid-1 mirror array by issuing:

mdadm --create /dev/md0 --level=raid1 --raid-devices=2 /dev/sda2 /dev/sdb2

In order to minimize the changes needed in the bubba configuration I simply created the same volume group and logical volume as before.

pvcreate /dev/md0
vgcreate bubba /dev/md0

In order to determine the size of the logical volume group I did

vgdisplay | grep 'Total PE'

In my case this value was 235797, so this gives us:

lvcreate -l 235797 -n storage bubba

I then created an ext3 file system by issuing the following command:

mkfs.ext3 /dev/mapper/bubba-storage

When this finnished, I was ready to mount the home partition back, but this time as a raid-1 mirror:

mount /home

Now I copied all file from /home2 back to /home

cp -a /home2/* /home/

I started nano again to edit /etc/passwd to change home2 back to home

nano -w /etc/passwd

Again, tried to ssh from a new terminal window in order to verify that it worked. Once I verified that it did, I issued a reboot just to see that it was all working. Which it did once the server was back on line. To check the state of the re-sync of the array I issued the following command:

cat /proc/mdstat

Now, it’s at 58.6% and will hopefully finish soon….

Posted by patrik in Howto