ctdb question, shared storage over iscsi

[ronnie sahlberg]

Rudy:

To clarify;
you can if you want to just use a single physical interface and mix
all three kind of traffics on it ;
ctdb, san-iscsi and public cifs/nfs access   but it is probable that
you will get less performance if you do so.
It should work but might be slower than it has to be.

In a test environment that may be acceptable but in a real live
production system you may want to separate
the traffic onto dedicated domains so that you get the maximum amount
of performance out of your (expensive) nas server.
Your call.


btw    i have a small blog about ctdb at    http://ronniesahlberg.blogspot.com/
where i will try to document some ctdb stuff from time to time

ronnie s

On Wed, Feb 6, 2008 at 8:33 PM, ronnie sahlberg
<ronniesahlberg at gmail.com> wrote:
> If possible, run CTDB on a private LAN dedicated to CTDB traffic only.
>
>  The reason for this is that you want to make sure that the ctdb node
>  to node latency to an absolute minimum since if CTDB slows down
>  then everything will slow down.
>
>  If you mix other bulk traffic within the same LAN as ctdb is using for
>  its private traffic this would add serialization and queueing delays
>  to the ctdb traffic and thus make it slower.
>
>
>  You CAN if you absolutely need/want to mix iSCSI bulk traffic on the
>  same network as the CTDB traffic  but the consequence is a risk that
>  the ctdb to ctdb traffic gets higher latency and this will slow down
>  both samba and ctdb.
>
>
>  Since you want iSCSI to a backend and this would be expected to be
>  massive huge bulk traffic, I would suggest you add a 10GbE nic eth2
>  and dedicate this NIC for the san,    thus using three networks
>  eth0: private network used only for ctdb
>  eth1: public network used for clients to connect to samba/nfs/iet
>  eth2: dedicated network for your iscsi san
>
>
>
>
>
>  On Wed, Feb 6, 2008 at 7:53 PM, Rudy Gevaert <Rudy.Gevaert at ugent.be> wrote:
>  > Hello,
>  >
>  >  I'm going to set up a gfs cluster together with ctdb.  eth0 will be the
>  >  interface for the node communication.  eth1 will host the public ip address.
>  >
>  >  My shared storage is an iscsi device.  Should I access that device
>  >  through eth0 or eth1.
>  >
>  >  Thanks in advance,
>  >
>  >  Rudy
>  >  --
>  >  -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
>  >  Rudy Gevaert          Rudy.Gevaert at UGent.be          tel:+32 9 264 4734
>  >  Directie ICT, afd. Infrastructuur ICT Department, Infrastructure office
>  >  Groep Systemen                    Systems group
>  >  Universiteit Gent                 Ghent University
>  >  Krijgslaan 281, gebouw S9, 9000 Gent, Belgie               www.UGent.be
>  >  -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
>  >
>