[Linux-cluster] Fwd: High Available Transparent File System

[Gordan Bobic]

On 10/04/2011 20:06, Meisam Mohammadkhani wrote:
> Dear Digimer,
>
> First of all, thanks for your reply.
> I'm not familiar with DRBD, but according to my little searches it's a
> solution for high availability in Linux operating system.

Considering you are asking on a Linux mailing list, that much should 
have been obvious pre-emptively. :)

> But, actually
> our application uses .net as its framework, so it is dependent to
> Windows-based operating systems and using the DRBD may facing us with
> some new challenges.

Then I fear your asking here may leave you rather out of luck. RHCS, GFS 
and DRBD are all Linux-only.

What you could potentially do is use the Linux storage servers as a back 
end with GFS on top of DRBD, and exporting the storage via Samba with 
CTDB. Your windows nodes could then connect to those. This will 
obviously double your hardware requirements, though.

> Also because of commodity nature of our machines,
> using the windows solutions needs a windows server on machines that is
> heavy for them. Using DRBD, force us to run our application in virtual
> machines that decrease the performance according to hardware spec. So we
> thought that maybe a "high available transparent file system" can be a
> good solution for this case. Even if the file system was not so
> cross-platform, we maybe be able to handle it with virtual machines
> which use the physical disks as their storage.
> I will appreciate your opinion.

If I am correctly following what you are saying, you want to use DRBD as 
the backing device which you want to export as a raw disk to your 
Windows VMs. That will only work if Windows have a clustering file 
system capable of concurrent access from multiple nodes. If you try to 
use standard NTFS on top of it, it will get corrupted as soon as you 
start writing to it from both nodes. You may be able to get some mileage 
out of Windows Cluster Shared Volumes, but how good that is (or whether 
it's any good at all for your application), I have no idea. You're 
better off asking that question on a Windows specific forum.

Gordan