ctdb question, shared storage over iscsi

[ronnie sahlberg]

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
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>