[CentOS] Possible to run iscsi-target and initiator on same server?

C Linus Hicks linush at verizon.net
Fri Oct 9 23:14:14 UTC 2009


On Fri, 2009-10-09 at 17:53 -0400, Ross Walker wrote:
> On Fri, Oct 9, 2009 at 5:37 PM, C Linus Hicks <linush at verizon.net> wrote:
> > I am trying to install Oracle RAC in a two node cluster for testing
> > purposes, so performance is not something that concerns me. I just want
> > to go through the process all the way to creating a database. I have all
> > the prerequisites except the shared storage and thought I'd give this a
> > try.
> >
> > I'm running:
> > - CentOS 5.3 kernel 2.6.18-164.el5
> > - iscsitarget-1.4.18-1
> > - iscsi-initiator-utils-6.2.0.868-0.18.el5_3.1
> >
> > I can discover and login to the node using iscsiadm on the server that
> > is not also running iet, and see the new scsi disk.
> >
> > When I try to login using iscsiadm on the server that is running the
> > ietd daemon, I see packets going over the lo interface in both
> > directions, but I get error 8 - connection timed out. Wireshark is
> > reporting TCP Previous segment lost errors with large sequence numbers
> > like 2999833 and 8999718.
> >
> > Has anybody tried this, and can anybody offer any help?
> 
> You can only do that if you use blockio for your targets, otherwise
> fileio will cause a deadlock on the page cache between the target's
> usage of it and the initiator's usage of it.

So for iet, that means /etc/iet/ietd.conf should define the Lun like
this:

Lun 0 Path=/dev/sdb,Type=blockio,ScsiId=asmdg,ScsiSN=dg0

If that's all it takes to make it do blockio instead of fileio, then
that is already the case. Deadlocks on the cache pages - wouldn't that
only affect I/O and not logging in?

Linus




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