topic Re: Remote data replication in Operating System - OpenVMS

Remote data replication

Thomas Kemp_1 — Thu, 17 Feb 2005 10:57:26 GMT

We're running ES47s with OpenVMS 7.3-1 and 7.3-2. We need to find an all encompassing solution to replicate data over 1500 KMs, asynchronously, and be guaranteed intact data in the event of a lost source of replication. No small order, I know. I was wondering if anyone else is doing this, and what products you're using, and if you're doing host based or array replication.

So far, we've looked at Steelhead, and Kashya, and several array based solutions suchas SRDF and the EVA's CA.

What are you guys doing?

TNA

Re: Remote data replication

Wim Van den Wyngaert — Thu, 17 Feb 2005 11:41:44 GMT

Keith Parris once told me that he heart about a 3000 miles cluster. It is unsupported but not impossible. All write IO's and cluster locks will be delayed ...
but if you have a light environment it might work.

Wim

Re: Remote data replication

Thomas Kemp_1 — Thu, 17 Feb 2005 12:12:16 GMT

Yeah, we've heard something similar to this, too. But, we have to stay in a supported configuration, and we're not running clusters.

Re: Remote data replication

Andy Bustamante — Thu, 17 Feb 2005 13:04:44 GMT

Have you investigated Reliable Transaction Router (RTR)? See http://www.hp.com/products1/rtr/index.html
for full details.

Re: Remote data replication

Thomas Kemp_1 — Thu, 17 Feb 2005 13:51:52 GMT

I sent in a request for more information about RTR, thanks.

Re: Remote data replication

Jan van den Ende — Thu, 17 Feb 2005 14:08:40 GMT

Thomas,

maybe the cluster option should NOT be ruled out immediately.

Keith Parris (from Engeneering) supplies some nice tools on the freewre CD which allow you to concentrate your locking local.

That way you CAN do HBVS with faily little latency.

Maybe you should contact him personally at
. hp com

He is guaranteed to ask the last thread of cloth from your body about your exact demands/wishes, and then come up with the solution that best fits YOUR situation.

hth,

Proost.

Have one on me.

Jan

Re: Remote data replication

Uwe Zessin — Thu, 17 Feb 2005 14:18:00 GMT

'little latency'? You must be kidding!

The speed of light in a fiber is calculated with 5 nanoseconds per meter. Unless I got my formula wrong, 1500 kilometers add up to 7.5 milliseconds for one way.

Re: Remote data replication

Jan van den Ende — Thu, 17 Feb 2005 15:31:42 GMT

Uwe,

that is about at the same scale as the differences between various hardware configs are.

The real pain developpes if you have to make several roundtrips for locking info before doing the actual IO. And _THAT_ is where those lock localisation stuff makes its gain!

And of course, 1.5 KKM is just a little walk further than 1.5 or even 150 KM.
_THAT_ is why you need to answer all kinds of questions, including some on cost, before deciding pro or contra.

fwiw,

Proost.

Have one on me.

Jan