RE: AS400 and EMC DMX with SRDF -- MIDRANGE-L

 
Actually, we are a quite complex environment with several iSeries
(v5r2)-with a mixture of old-new and external storage (ESS)- and zSeries
systems connected and exchanging transactions thru DRDA applications. Our
production iSeries is an i830.We are using MIMIX for the replication to our
i825 local HA system and to our disaster site. We decided to move the whole
production storage (iSeries and zSeries) to a DMX2000 which will be
replicated to a DMX1000 at the remote site and at the same time remove all
SPD resources.MIMIX will stay for the high availability.In order to keep
data between the two platforms "quite" synchronized, we had to consider the
use of a feature like SRDF, instead of our nicely performing and reliable
MIMIX. Additionally the splitted BCVS will give us the ability to perform
DRP tests without the need to destroy all backup data. On the other hand
SRDF requires the migration of the LS inside the DMX a procedure not
officially supported by IBM. We also decided to migrate our data by
straspbal (smooth and safe). Our concerns are about the load source
migration and the behavior of the backup system (i825) when it will have to
IPL with a completely different configuration.
 
EMC claims that their new products are much faster and reliable than IBMs
and so do some independent reports (ex.Gartner storage classification).
These new symmetrix DMXs are FC attached (no scsi). In any case the boxes
will be tested before accepted.
 
Thanks
 
 
 
-----Original Message-----
From: Bob [mailto:bob_larkin@xxxxxxxxxxxxx] 
Sent: Thursday, May 06, 2004 4:58 AM
To: Midrange Systems Technical Discussion
Subject: Re: AS400 and EMC DMX with SRDF
 
My experiences using EMC's Symettrix 5500 have been terrible. We just 
replaced the entire system, and now use internal DASD. We also purchased 
a second system and use MIMIX to replicate all of the data to an actual 
system that can take over in the event of a failure or maintenance.
 
I would question why you would want to SRDF the data for remote 
mirroring. Performance will probably be lousy, and if you lose the 
iSeries, all the data in the world is useless. In addition, purchasing a 
second system and HA software would probably be less expensive then the 
EMC Solution. And with HA you get added benefits, such as backups from 
the mirror system, allowing non-stop processing on the primary system. 
Software and OS upgrades can be done with minimal downtime by switching 
systems.
 
One last thought on external DASD. IBM's Shark line is comparable to EMC 
(IMHO), yet IBM does not recommend it's use on the iSeries, EXCEPT in a 
few special cases.  But EMC always recommends it. They have even pushed 
us to purchase a used system to create a migration tower, so we could 
use their equipment on  some 820 systems. This solution would have even 
further degraded the performance of the system, over using a natively 
attached DASD solution. They didn't care, as long as they got the sale. 
They didn't, and the systems have been running for almost three years, 
with over 2 Terabytes of DASD, we have not lost a bit yet. Did lose 
drives, but parity protection handled it quite well.
 
Tsopelas Anastasios wrote:
 
>Hi all,
> 
>Is there any real world experience about the migration of the internal
>storage of an iSeries to a Symmetrix DMX2000 external storage subsystem? 
>We plan to use SRDF for remote mirroring and this requires the migration of
>the load source into the DMX.
>If you can share any experience or thoughts it will be of a great value for
>us.
>Thanks, Tassos.
> 
> 


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