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Conference smurf::ase

Title:ase
Moderator:SMURF::GROSSO
Created:Thu Jul 29 1993
Last Modified:Fri Jun 06 1997
Last Successful Update:Fri Jun 06 1997
Number of topics:2114
Total number of notes:7347

1841.0. "details on "Disaster Tolerant Unix Cluster"" by XFMV01::AJITK () Fri Jan 24 1997 08:25

Hi

A recent CSS Newsletter talked about a "Disaster Tolerant 
Unix Cluster" order recently bagged by Digital. 

A large customer of ours is looking for a disaster tolerant
solution for its current Alphaserver 8400 running Digital Unix
and Oracle applications (all host based). The second server
is to be located within the same factory but another room
a few hundred meters apart. A couple of hours of switchover time 
can be tolerated. The Oracle database size is about 40GB.

In this context I will like to know the details of the CSS's
Disaster Tolerant Unix Cluster solution. The details I 
am interested in are :

1. Hardware and software components in the solution. A
configuration diagram showing how the servers and storage 
components are connected. 

2. When is this solution going to be in general availability ?

3. How does one go about proposing and implementing such a
solution ?

Will appreciate a pointer to the right people and location.

Also any detailed information on implementing disaster tolerance 
using Oracle products' features will help.

THanks in advance.

Ajit Kale

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1841.1KITCHE::schottEric R. Schott USG Product ManagementFri Jan 24 1997 09:3710
Hi

 See http://www-unix.zk3.dec.com/www/clusters.html#disaster

It will tell you to contact Steve Horn.  It will also point to
some other information...

regards

Eric
1841.2CSS FibreChannel solution16.181.128.8::jptFIS and ChipsMon Jan 27 1997 06:0116
	Last week we wrote three tenders for different customers. Solutions
	are FibreChannel based CSS tailored Available Server clusters.

	It takes 2-3 working days from CSS to propose a solution based on
	detailed specification for customer needs. In Europe Annecy CSS
	helps you to quote FC based clusters. They have been very 
	responsive to our needs, and it's about time, as we have lost
	several cases lately not having anything to offer in FC world.

	CSS solution is based on Seagate FC disks, Genroco Controllers and 
	Drivers, Gadzoox Hub and MIA. It gives you full SCSI address mapping
	(using LUN's aka HSZ family), it is full SCSI-2 compliant, supports
	target mode and emulates KZPSA functionality.

		-jari
1841.3CSS to the rescue!TROOA::MSCHNEIDER[email protected]Sat Feb 08 1997 22:132
    Yes from the powerpoint presentation available on the web page it looks
    like CSS has put together a very nice solutions.
1841.4KITCHE::schottEric R. Schott USG Product ManagementSun Feb 09 1997 21:366
Hi

 I suggest you speak with Steve Horn.  The CSS solution is not
qualified with ASE.  It hopefully will be done in the future, but
you should discuss you customer needs with Steve Horn asap.

1841.5Some caveats....NETRIX::"[email protected]"Steve HornWed Feb 12 1997 11:5316
We are indeed planning on testing the CSS Annecy Fibrechannel configuration
with ASE.  Firm dates are not yet available, but I will post them here when
they are (as well as on the DT Web page).

But here is a significant caveat:  if we test this configuration with ASE and
it passes totally...you still do not have a true Disaster Tolerant solution.
You do have a Highly Available cluster that can be stretched over a longer
distance...but without a 'DT Safe' mirroring method (see the web page for 
definition) you have some significant exposures.  Indeed, if you use the
database replication utilities (which are DT Safe) for updating the backup
site
you don't need the Fibre!!

Steve
[Posted by WWW Notes gateway]
1841.6Sizing the problemANNECY::CHABORD_DDominique CHABORD @AEOThu Feb 13 1997 10:1634
        Hi,
        
        
        RE .0: You can get first info on what is delivered on projects in
        aeobn0::eic$tn:[ha_osf.disastol]
        as well as a documentation of known limitations.
        
        RE .-1:
        I am confirming what Steve says: With LSM, there is potential loss 
        of data in case of disaster. For those interested in knowing how 
        much and how often, please keep on reading.
        
        If you imagine a disaster like a bomb, there is no problem, because 
        the computer stops at the same time as the disks.
        
        If you imagine a disaster starts as a sequence of failures, you 
        have several cases:
        	- the computer fails first: no problem
        	- local disks fail before link to remote disks: no problem
        	- link to remote disks breaks first: here is the problem, 
        because the computer will write data on the local disk only.
        
        In this third case, there is a gap between the failure and the 
        "engine stop". I imagine a period of a few seconds, but it is 
        enough to say that it is not DT safe.
        
        All our customers so far have accepted this risk. For those who 
        wouldn't, one can complement what we've done or study an 
        alternative, like data replication at db level. If we make progress 
        we'll post it.
        
        
        dominique