[Linux-cluster] GNBD, how good it is ?

[Kresimir Kukulj]

Quoting Benjamin Marzinski (bmarzins at redhat.com):
> On Fri, Jul 09, 2004 at 03:53:00PM +0100, Gareth Bult wrote:
> > :)
> > 
> > I do appreciate all that, however there are some press releases out
> > there that are not so clear ..
> > 
> > There is certainly an implication in the news items I've seen that this
> > is "THE GFS" code .. as opposed to being a new and unstable version ..
> > 
> > .. Incidentally, I was being kind - I've had many kernel crashes, even
> > after getting it going ..
> > 
> > Regards,
> > Gareth.
> 
> The code you are using is not the code currently being sold by redhat.
> That is the 6.0 code. You can download that in SRPM form at
> ftp://ftp.redhat.com/pub/redhat/linux/enterprise/3/en/RHGFS/i386/SRPMS/
> 
> There is fairly complete documentation for this code. However it does not use
> the DLM.  Instead, GULM handles all the cluster manager issues.  This code only
> runs on 2.4 kernels.
> 
> The CVS code is going to be sold starting with RHEL 4. Some of the components,
> like the dlm are just now gotten out of the development stage. Others, like

Is this new DLM still dependent on single lock storage or is it distributed
(like in OpenDLM) ?

> gnbd have been drastically rewritten.  We REALLY appreciate all the testing

You are saying that GNBD is rewritten. How does it compare to GNBD in
GFS-6.0 (version sold by RedHat) in stability, performance, features ?

> that people are doing on these pieces, however, if you are trying to run
> something in production, I would encourage you to run the 6.0 code.

Thanks, I'll look into it.


Does anyone use some software based shared storage like GNBD, iSCSI
or HyperSCSI as an alternative to expensive FibreChannel hardware ?
If you do, can you describe your experiences (how stable it is, performance,
which implementation)... I believe this information will be interesting to
other people too.

Browsing the net, there are couple of variants of network block device (NBD,
ENBD, DRBD) but they don't support more than one client (and both sides
cannot be used at the same time).

There is of course GNBD:
  - OpenGFS version - not maintained anymore.
  - GFS-6.0 version sold by RedHat (2.4 kernel).
  - GFS-XX version from re-released sources of GFS ported to 2.6 kernel.

There are two 'target' implementations of iSCSI protocol:

  - http://unh-iscsi.sourceforge.net/
    initiator implementation is their primary development. They have target
    implemented but is currently mostly used to test the initiator. Runs on
    2.4 and 2.6 kernels.

  - http://www.ardistech.com/iscsi/
    iSCSI target implementation for 2.4 kernel's only.

  - http://linux-iscsi.sourceforge.net/
    iSCSI initiator implementation for 2.4 and 2.6 kernels.


Anything else?

-- 
Kresimir Kukulj                      madmax at iskon.hr
+--------------------------------------------------+
Old PC's never die. They just become Unix terminals.