In the beginning I opted for NFS as shared file system, then decided to go for OCFS2 which is open source, maintained by Oracle, and available under GPLv2.

Some Pros/Cons of NFS, GFS2 and OCFS2 (from Dublin OSS barcamp) :

NFS

• Pro: standard, cross-platform, easy to implement
• Con: Poor performance, single point of failure (single locking manager, even in HA)

GFS2

• Pro: Very responsive on large data files, works on physical and virtual, quota and SE-Linux support, faster than EXT3 when I/O operations are on the same node
• Con: Only supported with Red Hat, Performance issues on accessing small files on several subdirectory on different nodes

OCFS2

• Pro: Very fast with large and small data files on different node with two types of performance models (mail, data file). Works on a physical and virtual.
• Con: Supported only through contract with Oracle or SLES, no quota support, no on-line resize

First we need to install OCFS2 tools :

sudo apt-get install ocfs2-tools

There is another package ocfs2console that you want to install to configure the cluster via GUI, but since I’m using ubuntu server I’m skipping this to configure my cluster manually.

Create on every node attached to storage /etc/ocfs2/cluster.conf

sudo vi /etc/ocfs2/cluster.conf

With the content below, only replace node1 and node2 with their respective names and IP for each node :

node:
name = node1
cluster = ocfs2
number = 0
ip_address = 10.10.0.0
ip_port = 7777
node:
name = node2
cluster = ocfs2
number = 1
ip_address = 10.10.0.1
ip_port = 7777
cluster:
name = ocfs2
node_count = 2

Now you reconfigure ocfs2-tools with the default values :

sudo dpkg-reconfigure ocfs2-tools

then restart services :

sudo /etc/init.d/o2cb restart
sudo /etc/init.d/ocfs2 restart

If your fiber card connected to your host/storage, and virtual disks created and presented you should run fdisk to see it :

$ sudo fdisk -l
Disk /dev/sda: 1073.7 GB, 1073741824000 bytes
255 heads, 63 sectors/track, 130541 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: 0x02020202

the result have been truncated to show only one virtual disk, and you might see multiple /dev/sda, /dev/sdb, /dev/sdc… according to your configuration in addition to your local hard disks. What I have done is creating a 1TB partition that I will share between my two nodes :

$ sudo fdisk /dev/sda

In fdisk menu choose “n” for new partition, and choose your partition size according to your requirements. Then use “w” to write changes and exit.

Finally we create a ocfs2 partition table :

$ mkfs.ocfs2 /dev/sda

mount your partition :

$ sudo mkdir /archives
$sudo mount -t ocfs2 /dev/sda /archives

or you can add it to fstab to mount automatically on boot :

$ /dev/sda /archives ocfs2 _netdev 0 0

The _netdev option is used here to prevent the system from attempting to mount these file systems until the network has been enabled on the system.

You want to test your new partition, and you will notice that every file/folder created on node1 is automatically available on node2, and vise-versa.

Enjoy !

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The first session was about Sun SPARC enterprise servers, and I liked the idea of supporting mix of processors versions in the M4000, M500 and M9000 (the M series servers) – and it’s only Sun that offer this compared to IBM and HP. Some benchmarks also in this session and was very informative; also covered different aspect of the M-Series and CMT servers for single-threaded and multi-threaded.

In the second session the Datacenter Architect talked about Datacenter efficiency through virtualization. Andy talked about different level of virtualization Servers, Storage, and Network, in addition to virtualization tool Sun VDI software and Sun Ops Center. The business case in the end was very interesting showing 14% ROI in the first year only. There is something I noticed that virtualization tools are available free with Open Solaris, and coming soon to Solaris; and you don’t have to pay more to use them ! It’s something like when you buy a new car, then you try to use the Radio and they tell you have to pay more for this feature. Well, I totally agree with Andy and find it really ridiculous to do this; especially that I have a similar problem with HP Storage and the way they limit licencing to a fixed number of TB – so to add more capacity we’ll need a new license.

In the last session, Thomas talked about Sun Storage 7000 Unified Storage Systems. Almost all speakers was insisting on the ZFS – the famous Sun File Systems; obviously it was mentioned more frequently with the storage session. I liked especially the Enterprise SSDs, which eliminates storage bottlenecks. The ZFS pool guarantee a better performance for writes via the ZIL pool and reads via L2ARC pool – both connected to SSDs in addition to a third pool with cheap HDs.

The last session was about Sun FlashFire; also by Thomas. There was a case study of the KAUST presented by Mohammed Abdel Aal; Manager KAUST IT Computing Infrastructure. Mr Mohammed talked more about KAUST research strategy, but there is something that I liked most in KAUST IT requirements “No legacy systems, no legacy thinking”.

Overall it was great meeting IT professionals. I have already worked with Sun servers and Solaris, but I don’t have previously good knowledge of their hardware architecture. I was only familiar with ZFS and Open Solaris.

I didn’t stay for the lunch, but I expect it to be great too.

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