Bi-directional replication

[waugh]

In unidirection remote copy in 3PAR
1) create the VV in primary side and secondary side. Create the replication set and teplicate from primary side to seconday.


query : AS per my understanding no need to craete the VV in secondary side, While creating the RCFC it will give the option whether to create the seconday side lun automatically or not.


My query is how to set up bidiraction replication.
query 1) In bidirection repliaction do i need to create the primary lun at both side or how it will replicate.

What do you mean by bidirection replication. As per my understadning data will be replicate from primary dise side to secondary (DR side). During DR time will failover the primary side to DR side by changing the role for luns eg. in HP xp10000 or hictachi will do horctakover it will swap the role p-vol to S-vol. So is it the same bipdirecation mean or somthing differnet.

When we can use the bi-direction replication?


Thanks,
Waugh

[Schmoog]

All bidirectional replication means is that an array is not necessarily a source or target. You can have vv's on array a replicating to a target on array b, and at the same time have vv's on array b replicating to a target on array a

[waugh]

Hi All,

In bidirectaional replication take a exampls of one database
The datbase size is 500GB and stoarge team allocated 100 GB *5 =500GB lun. now my query is on bidirectional

par01---primary site
par02---secondary site

my application is running on primary site, so can i replicate 3 luns from par01-----par02 and remaining two luns from par02----par01.
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second case. Bidirectionl mean we have to failover the 5 Luns to par02 and replicate from par02 to par01. The application will be accessible from par02 site .

Regards,
Waugh

[RitonLaBevue]

bidirectionnal means you can replicate from A to B and B to A BUT not for the same VVs at same time.
So you got 5 VVs in same RCopyGroup replicating from A to B.

So, your second case is the right one.
What about talking with your storage admins ?

[waugh]

Hi All,

Could you please let me know how then 3 PAR bidirectional replication is different than the other storage boxes like Hitachi VSp, EMC. IN Any storage we can failover the application at remote site and replicate from remote site . Nothing is new here in 3par in terms of bidireactional replication.

Best Regards,
Waugh

[Schmoog]

Who told you it was any different from emc/netapp/hds?

3par has many competitive differentiators, bidirectional replication is not, and has never been, and will never be, one of them

[RitonLaBevue]

Maybe... Talk to Pure people

[Schmoog]

Perhaps you(Waugh) thought that bidirectional replication means you can access the lun on both the source and target side simultaneously?

If so, that setup is as mythical as the user awhile back asking about zero RTO. It is not possible, no matter who the manufacturer is. You might be able to fake it by merging the fabrics over a private fiber and accessing the primary site array from the dr site, but that is a horrible idea from a performance and reliability perspective.

[afidel]

Perhaps you(Waugh) thought that bidirectional replication means you can access the lun on both the source and target side simultaneously?

If so, that setup is as mythical as the user awhile back asking about zero RTO. It is not possible, no matter who the manufacturer is. You might be able to fake it by merging the fabrics over a private fiber and accessing the primary site array from the dr site, but that is a horrible idea from a performance and reliability perspective.

Take a look at vplex before you say it's impossible. Of course this design gets even easier when we get VMware vvols because the unit of access and replication becomes the vmdk rather than the lun.

[Schmoog]

True, san virtualization like vplex/netapp v series/hds usp-v can make it almost possible in that they use the back end sans like mirrors.

Let me rephase, without complex and expensive san virtualization and even more complex conflict resolution, it's not possible.

If it's possible with vplex, then how does vplex resolve it if db server a in site a writes to a block on san a at the same time db server b in site b writes to the same block on san b