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Subject: RE: Data Mirror over dark fibre not using DMIP with Filers not clustered together.
Date: Thu, 14 Dec 2006 09:14:08 -0800
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Thread-Topic: Data Mirror over dark fibre not using DMIP with Filers not clustered together.
thread-index: AccfAlf+mzadI8FCQbOb8w2BcOvrIQAPlNJWABVMBZAAAPUcMAAAPm7QAAIJ1IwAAAYe0A==
From: "John Culp" <john.culp@onstor.com>
To: "Jerry Lopatin" <jerry.lopatin@onstor.com>,
	"Doug Cook" <doug.cook@onstor.com>,
	"Jonathan Goldick" <jonathan.goldick@onstor.com>,
	"Tim Gardner" <tim.gardner@onstor.com>,
	"dl-cstech" <dl-cstech@onstor.com>,
	"Jay Michlin" <jay.michlin@onstor.com>
Cc: "Paul Hammer" <paul.hammer@onstor.com>

Agreed.  I think we have an good opportunity here.  I was looking
conceptually if it was something we think we could do with little effort
(hopefully).

PVR coming soon.=20


John Culp=20

System Engineer=20
940-239-7489 Office=20
972-523-4287 Cell=20
john.culp@onstor.com=20


-----Original Message-----
From: Jerry Lopatin=20
Sent: Thursday, December 14, 2006 11:11 AM
To: Doug Cook; Jonathan Goldick; John Culp; Tim Gardner; dl-cstech; Jay
Michlin
Cc: Paul Hammer
Subject: Re: Data Mirror over dark fibre not using DMIP with Filers not
clustered together.

All,

I think the best way to think about this is that it isn't something we
currently officially support.  It may work, but there may be issues.
Let's be careful about selling something that lacks official support.

John, if you think there is a good deal here, please file a PVR, and
we'll look at the effort needed to officially support it.

Thanks

Jerry
--------------------------
Sent from my Blackberry; please excuse my typing!=20

-----Original Message-----
From: Doug Cook
To: Jonathan Goldick; John Culp; Tim Gardner; dl-cstech
Sent: Thu Dec 14 08:14:18 2006
Subject: RE: Data Mirror over dark fibre not using DMIP with Filers not
clustered together.

Isn't this what Kroger is doing?  Aren't they using SAN extenders to
make the storage at the DR site look like it is in the same room with
the ONStor cluster?  I believe they are using DM to mirror a volume from
one data center to the off site.  Then, as Jonathan said, in the event
of a declaration they would have to use vol_import, etc.
=20
DC

________________________________

From: Jonathan Goldick
Sent: Thursday, December 14, 2006 11:11 AM
To: John Culp; Tim Gardner; dl-cstech
Subject: RE: Data Mirror over dark fibre not using DMIP with Filers not
clustered together.



The only way to do this is to make the DR LUN(s) visible and owned by
the primary cluster.  It is unlikely that we would have a FC-based
mirroring problem at that distance since we can handle serious latency
in this layer, but there may be SAN/LUN discovery issues that we have
not seen before as this has never been attempted.  If we went this
route, the mirror target would not be usable by the DR cluster without
importing it in the event of a failure.  They would then have to create
new NFS/CIFS shares at that time and there would be no ability to resync
the mirror after the primary cluster came back.

=20

=20

=20

________________________________

From: John Culp=20
Sent: Thursday, December 14, 2006 7:44 AM
To: Tim Gardner; dl-cstech
Subject: RE: Data Mirror over dark fibre not using DMIP with Filers not
clustered together.

=20

The data rate change is estimated currently at 15% - 20% per day.  While
that is a file number and not block number we shall see what the real
block change rate is soon.

=20

The customer is WANTING to use the FC because they do not want to use FP
ports to transfer data.  They spent the $$$ for the direct Fiber run and
just want to try and use it more than they are.  The idea is separation
of client access via the front end and replication / data volumes via
the back end.

=20

The thought is if we can DM between to volumes that are not in the same
VSVR via IP, is it possible to do it over the FC and if not how
difficult would that be.

=20

The customer knows we do not currently do this.  If this is simply just
not possible, then I can tell them that.

=20

John Culp=20

System Engineer=20
940-239-7489 Office=20
972-523-4287 Cell=20
john.culp@onstor.com=20

=20

=20

________________________________

From: Tim Gardner=20
Sent: Wednesday, December 13, 2006 11:39 PM
To: John Culp; dl-cstech
Subject: RE: Data Mirror over dark fibre not using DMIP with Filers not
clustered together.

Data Mirror is only supported between volumes in the same cluster.

More over, the volumes have to belong to the same virtual server.

=20

I don't know if we have any experience connecting a filer to storage=20

that is so far from the filer.

=20

Is their rate of change such that using DMIP is not practical?

=20

=20

________________________________

From: John Culp
Sent: Wed 12/13/2006 2:02 PM
To: dl-cstech
Subject: Data Mirror over dark fibre not using DMIP with Filers not
clustered together.

Current situation:

=20

current DMIP customer has primary and DR site on their campus
environment.  Primary site is a 2260HA, DR site is a single 2260.  DR
site is 1 mile away (it is a BIG Campus).  They are having current DMIP
issues.  The DR site is NOT clustered to the primary site.

=20

What they would LIKE to do

=20

Let me preface this first with, I know it is 5280 ft.  The customer
wants to separate replication traffic from user traffic.  This is
currently no being done because they are dedicating a single GiGE for
DMIP.  They WOULD LIKE to run Data Mirror over the dark fibre they have
directly between the primary and DR site.  They are currently doing this
with their block data in a synchronous solution on Xiotech.

=20

1. Can we use Data Mirror via FC to volumes not in the same Cluster?

2. If their FC environment is fast enough with low latency is there an
issue?

=20

If we could do this, it would be very helpful to the customer.

=20

John Culp=20

System Engineer
john.culp@onstor.com <mailto:john.culp@onstor.com>=20
office: 940-239-7489
cell: 972-523-4287
ONStor, Inc.
NAS for Enterprise
3311 Chalkstone Cove| Corinth, TX 76208
main: 940-239-7489 | fax: 940-239-7527=20

=20

