[Linux-cluster] GFS Volume Over NFS

[Mathew, Gigi (JSC-EG)[Jacobs Technology]]

Rafael:

Thanks for your reply.  I believe NFS over GFS2 should be the solution.

Now I have a question about GFS performance fine tuning.  Is there any documents do you recommend?

Thanks

-- Gigi

-----Original Message-----
From: linux-cluster-bounces at redhat.com [mailto:linux-cluster-bounces at redhat.com] On Behalf Of Rafael Micó Miranda
Sent: Sunday, September 27, 2009 4:19 AM
To: linux clustering
Subject: Re: [Linux-cluster] GFS Volume Over NFS

Hi Gigi,

El vie, 25-09-2009 a las 19:09 -0500, Mathew, Gigi (JSC-EG)[Jacobs
Technology] escribió:
> Hi:
> 
>  
> 
> I am configuring a Dell EqualLogic iSCSI array in a RHEL 5.3 platform
> with two GFS2 volumes with RedHat Cluster Suite using DRAC (primary)
> and APC (secondary) fencing devices.  In my cluster configuration I
> have DELL Servers (PE R900, PE6800, PE2800, PE1950) Blades (PE M1000,
> PE1955, PE1855).  Now I have few workstations (Precision 7500,
> Precision 5500,  Precision 690) which I would like to share the above
> GFS2 volume over NFS (why?  They are not in the same location and
> currently I use NIS/YPBIND/AUTOFS).  Why should I share it? (Because I
> have user home directories on this GFS2 volume, which has to seen from
> these workstations as they login).  What are the options I have? How
> do I achieve it?  I had seen how to share an NFS over GFS, but NOT the
> other way. Any suggestion will be greatly appreciated.
> 
>  
> 
> Thanks
> 
>  
> 
> Gigi Mathew
> 
> 
> --
> Linux-cluster mailing list
> Linux-cluster at redhat.com
> https://www.redhat.com/mailman/listinfo/linux-cluster

Maybe i'm understanding you wrong, let me explain what i have understood
from your explanation:

1.- You have several servers sharing iSCSI volumes from an iSCSI array.

2.- This servers use GFS2 as filesystem on this volumes to share,
between themselves, the information in them

3.- You want to make other computers, workstations, get access to this
info. They are not in the same location/network so they can not access
the iSCSI array by themselves.

4.- You plan to share the iSCSI volumes from the array through a NFS
export via the servers which already have access to them, so
workstations will get access to the information via NFS.

Is this right?

If so, you should have a look at this document: 

http://www.redhat.com/docs/en-US/Red_Hat_Enterprise_Linux/5/html/Configuration_Example_-_NFS_Over_GFS/index.html

NFS over GFS2 is, in my opinion, exactly what you need.

The other option i think you are thinking about, GFS2 over NFS, cant be
done. 
GFS is a filesystem you use over a device or partition. NFS is a file
sharing protocol you use to export an already existing filesystem (EXT2,
EXT3, XFS or GFS itself). When you mount a NFS volume you don't have
access to a device, so you cant use GFS on it when already mounted. 

You maybe are thinking in GFS2 over GNDB (global network block device)
or GFS2 over DRBD (distributed redundant block device), but i think
previous suggestion is simpler than this one. You can also have a look
to this approach here:

http://www.redhat.com/docs/en-US/Red_Hat_Enterprise_Linux/5.4/html/Global_Network_Block_Device/index.html

I hope this helps.

Cheers,

Rafael


-- 
Rafael Micó Miranda

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