Ubuntu RAIDZ1-0 wtih ZFS

For my new machine I had a 64 Gb SSD and 4 2Tb drives that I wanted to utilize as storage.  What I discovered was just how easy it is to install Zorin on the SSD and use ZFS to create  a RAIDZ1-0 storage pool managed by ZFS.

The Zorin installation was straightforward and uneventful.  For those of you unfamiliar with Zorin it is an Ubuntu variant with a gnome interface.  The pleasant surprise was that since the new motherboard was capable of supporting the 6Gb/s transfer rate of the SSD.  The OS was very responsive and snappy.  This is double the previous speeds from the SATA II only MB that was replaced.

Wtih Zorin in place the next issue was how to utilize the 4 disk array effectively.  I tried to find drivers in linux to utilize the disks in a hardware RAID configuration since the new motherboard claimed support for this.  Google could not help me and I gave up on the idea of hardware RAID.  I was looking at the disk utility application and trying to figure out how to assemble the 4 drives into an array and use it that way.  This was not intuitive.  That is a kinder way to say, it was not obvious and I did not like all the steps involved, despite the fact that I had done this before and made it work.

So I took a look at the ZFS on Linux site and decided to give that a try.  I had enough experience using zfs and storage pools to know this was in fact the ultimate and as the name implies the last word in storage systems.  If anyone cares to debate this claim I would really like to learn more about any of the high end alternatives available on linux.

Again I was pleasantly surprised and quite impressed with exactly how far the ZFS on Linux project has come.  I was able to download the ZFS source, compile and install it exactly as noted in the documentation.  Once ZFS is installed it was pretty much standard zfs and zpool commands to get this setup in a way that I think effectively takes advantage of the SSD and the 4 disk array.  Even though my /home/ivan directory is on the SSD, I wanted all storage on the slower but much larger capacity drive array.

I created the initial storage pool by invoking the zpool create, using -f for force, and the standard pool name of tank.  Since I had 4 disks I could choose raidz and then listed the devices to be part of the pool.

zfs create tank/downloads

zfs mount /tank/downloads /home/ivan/Downloads

Since the Downloads directory was empty ZFS did not complain.  If the /home/ivan/Downloads dir had not been empty ZFS would not perform the operation.  I created a few more and decided to do a few checks.

df -h -t zfs

Filesystem              Size      Used Avail   Use% Mounted on

tank                        5.4T      0       5.4T   0%      /tank

tank/repository         5.4T      0       5.4T   0%      /tank/repository

tank/downloads        5.4T  476M     5.4T   1%      /home/ivan/Downloads

tank/documents       5.4T     0        5.4T   0%      /home/ivan/Documents tank/documents/professional

                              5.4T     0        5.4T   0%      /home/ivan/Documents/professional tank/documents/tessaract

                              5.4T     0        5.4T   0%      /home/ivan/Documents/tessaract

tank/workspace       5.4T     0        5.4T   0%      /home/ivan/workspace

tank/software          5.4T     0        5.4T   0%      /home/ivan/software

tank/pictures           5.4T     0        5.4T   0%      /home/ivan/pictures

tank/notes              5.4T     0       5.4T   0%       /home/ivan/notes

Some of the file systems listed were not in the exact configuration in this listing that I wanted.  fortunately it is very easy to adjust them to obtain the desired configuration in the end. 

ZFS includes a facility called scrub that does a very detailed check of the data integrity and fixes it if required.  The time involved in this operation increases with the amount of data involved.  In this case since the disks, indeed the entire system was brand new it only takes a few milliseconds as shown in the output from scrub.  Note that the use of scrub should be automated and performed on a weekly basis or so.

zpool scrub tank

root@zaarexx:~# zpool status

  pool: tank

 state: ONLINE

 scan: scrub repaired 0 in 0h0m with 0 errors on Tue Jul 12 22:41:20 2011

config:

NAME        STATE     READ WRITE CKSUM

tank        ONLINE       0     0     0

  raidz1-0  ONLINE       0     0     0

    sda     ONLINE       0     0     0

    sdb     ONLINE       0     0     0

    sdd     ONLINE       0     0     0

    sde     ONLINE       0     0     0

errors: No known data errors  

Any comments or corrections are appreciated.