2007/6/21, Linux Lover <favorite.linux@gmail.com>:

On 6/21/07, Flavio <fbcyborg@gmail.com> wrote:
Hello Linux Lover,
I have created 2 nodes and a shared file, and run the two kernel with the following commands:
./linux mem=256M ubda=root_fs_1 ubdb=ocfs2_fs eth0=mcast
./linux mem=256M ubda=root_fs_2 ubdb=ocfs2_fs eth0=mcast

I guess you are using 2 separated kernel images... isn't it? I see you are using ./linux in both cases.

I use the same kernel image. It is OK by now and I think a program can be executed twice in Linux, isn't it? ;)

I'm sorry, I was confused.. Yes, that's right. Actually you are running the same process for two different filesystem.

I can mount the ocfs2_fs on node1, but when I mount it on node2, the error msg is:
ubdb: Can't open "ocfs2_fs": errno = 11
mount.ocfs2: I/O error on channel while opening device /dev/ubdb1

What kind of HPC clustering system are you using? OpenSSI? OpenMosix??? 

Do I really need this? ocfs2_fs is just a normal file like the "root_fs" and OCFS2 is already a cluster file system.

Ah, OK, I'm not really expert in HPC clustering because my "research team" is composed by many people, one for virtualization and terminal servers (like me), one for HPC clustering and others for something else....
Anyway, I thought it would be useful to set up a real HPC system like OpenMosix on a UML kernel but maybe your choice is better.

I strongly suggest you to subscribe to this mailing list, in order to get further advices to do what you exactly need. Jeff Dike and Paolo Giarrusso and Chris Marshall are expert more than me on other problems. Let them read your posts.

And Can anyone tell me how to setup a share disk which has direct read/write access for multiple nodes?

You can use samba or nfs too for communications between two UML machines and the host system too. Sharing two filesystem without using them maybe not safe (in my opinion). UML kernel supply for a module which allows to get into the host system, but I tink it's not safe. Maybe it isn't in your case.
UML utilities supply for a console wich allows to get into the guest system from the host; try to do that and to mount the part which you gained access somewhere and try to share it.
I don't know if it's a good idea but it maight be a begin point.

To be frank, I am trying to setup the OCFS2 environment on UML and I am not sure whether samba or nfs can keep the DLM and other things perfect in a cluster. I have found that Jeff has also written a document about how to setup an OCFS2 cluster using UML.
http://linuxhelp.blogspot.com/2006/05/book-review-user-mode-linux.html
The 12th chapter is a rather specialized topic and is aptly titled "Specialized UML configurations". Here one gets to know how UML could be used to explore the software limitations on ones machine like the hard limits in the Linux networking subsystem, the performance of large memory UML instances on ones machine as well as setting up a small UML cluster using Oracle's ocfs2.

So are there anyone in this list have read that chapter and kindly generalize the normal setup steps for me? Thanks.

Obviously Jeff!!!!
He often posts messages in this list.
Subscribe you too!!!
They also recently solved the Spam problem delivered through this list! Now it's perfect, and I don't receive spam.

btw, I don't subscribe to this mail list, so could you please reply directly to my e-mail? thanks.

For me, that's no problem... I don't know if it's the same for the others.

I have already subscribed to this list now since I decided to know more about UML. :)


Ah, OK!!!! So, don't care of my previous suggestions!

Flavio

www.vdd-project.org