[Linux-cluster] Questions about GFS

[Mark Hlawatschek]

Greg,

you can use a diskless shared root configuration with gfs. This setup would 
enable you to add cluster nodes as you need them.
Have a look at  http://www.open-sharedroot.org/ 

Mark

On Wednesday 12 April 2006 17:21, Greg Perry wrote:
> Thanks Bowie, I understand more now.  So within this architecture, it
> would make more sense to utilize a RAID-5/10 SAN, then add diskless
> workstations as needed for performance...?
>
> For said diskless workstations, does it make sense to run Stateless
> Linux to keep the images the same across all of the workstations/client
> machines?
>
> Regards
>
> Greg
>
> Bowie Bailey wrote:
> > Greg Perry wrote:
> >> I have been researching GFS for a few days, and I have some questions
> >> that hopefully some seasoned users of GFS may be able to answer.
> >>
> >> I am working on the design of a linux cluster that needs to be
> >> scalable, it will be primarily an RDBMS-driven data warehouse used
> >> for data mining and content indexing.  In an ideal world, we would be
> >> able to start with a small (say 4 node) cluster, then add machines
> >> (and storage) as the various RDBMS' grow in size (as well as the use
> >> virtual IPs for load balancing across multiple lighttpd instances.
> >> All machines on the node need to be able to talk to the same volume
> >> of information, and GFS (in theory at least) would be used to
> >> aggregate the drives from each machine into that huge shared logical
> >> volume).
> >>
> >> With that being said, here are some questions:
> >>
> >> 1) What is the preference on the RDBMS, will MySQL 5.x work and are
> >> there any locking issues to consider?  What would the best open source
> >> RDBMS be (MySQL vs. Postgresql etc)
> >
> > Someone more qualified than me will have to answer that question.
> >
> >> 2) If there was a 10 machine cluster, each with a 300GB SATA drive,
> >> can you use GFS to aggregate all 10 drives into one big logical 3000GB
> >> volume?  Would that scenario work similar to a RAID array?  If one or
> >> two nodes fail, but the GFS quorum is maintained, can those nodes be
> >> replaced and repopulated just like a RAID-5 array?  If this scenario
> >> is possible, how difficult is it to "grow" the shared logical volume
> >> by adding additional nodes (say I had two more machines each with a
> >> 300GB SATA drive)?
> >
> > GFS doesn't work that way.  GFS is just a fancy filesystem.  It takes
> > an already shared volume and allows all of the nodes to access it at
> > the same time.
> >
> >> 3) How stable is GFS currently, and is it used in many production
> >> environments?
> >
> > It seems to be stable for me, but we are still in testing mode at the
> > moment.
> >
> >> 4) How stable is the FC5 version, and does it include all of the
> >> configuration utilities in the RH Enterprise Cluster version?  (the
> >> idea would be to prove the point on FC5, then migrate to RH
> >> Enterprise).
> >
> > Haven't used that one.
> >
> >> 5) Would CentOS be preferred over FC5 for the initial
> >> proof of concept and early adoption?
> >
> > If your eventual platform is RHEL, then CentOS would make more sense
> > for a testing platform since it is almost identical to RHEL.  Fedora
> > can be less stable and may introduce some issues that you wouldn't have
> > with RHEL.  On the other hand, RHEL may have some problems that don't
> > appear on Fedora because of updated packages.
> >
> > If you want bleeding edge, use Fedora.
> > If you want stability, use CentOS or RHEL.
> >
> >> 6) Are there any restrictions or performance advantages of using all
> >> drives with the same geometry, or can you mix and match different size
> >> drives and just add to the aggregate volume size?
> >
> > As I said earlier, GFS does not do the aggregation.
> >
> > What you get with GFS is the ability to share an already networked
> > storage volume.  You can use iSCSI, AoE, GNBD, or others to connect
> > the storage to all of the cluster nodes.  Then you format the volume
> > with GFS so that it can be used with all of the nodes.
> >
> > I believe there is a project for the aggregate filesystem that you are
> > looking for, but as far as I know, it is still beta.
>
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-- 
Gruss / Regards,

Dipl.-Ing. Mark Hlawatschek
Phone: +49-89 121 409-55
http://www.atix.de/
http://www.open-sharedroot.org/

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