Re: SRDF and Oracle Rac 11gR2

SRDF is very popular for good reasons. Like others said SRDF does what it says on the tin, and supports more than Oracle. As a DBA I was always a bit worried since I had to rely on the storage admins and had little/no visibility about the status of the replication. I used to cross fingers, hoping that replication has been set up and maintained correctly. Testing helps you find out if all is working as expected (testing is so useful in so many cases!)

I personally prefer Data Guard: I can open the standby read-only any time to see if all is ok. The granularity in Data Guard is the database. You have to provision storage per database with SRDF to get the same granularity; ASM can make matters a bit more complex, ideally you'd have separate disk groups per database. That's my opinion, the storage team usually has a different one :) Whichever way you go, be aware that consolidating databases on the same server might require more involvement depending on business requirements for DR (testing).

In the case of RAC we did exactly as has been described on the standby: install Clusterware with an OCR/voting file disk group only, +DATA and +RECO were replicated to the DR site but the R2s are not read-write. The only downside I could find was the need to perform disk discovery which can be tricky depending on your OS and release.

Hope this helps,

Martin

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Martin Bach
Enkitec
martincarstenbach.wordpress.com

On 27/01/14 22:32, Matthew Zito wrote:


> Again, it's been a long time, but you used to be able to split off a mirror

> periodically and open the database read-only or read-write, then shut it

> down and resync periodically (and the resync is obviously really fast if

> it's read-only).

>

> But it's all point-in-time, and there's nothing comparable to active

> dataguard.

>

> Matt

>

>

> On Mon, Jan 27, 2014 at 4:29 PM, Andrew Kerber <andrew.kerber_at_gmail.com>wrote:

>

>> We are still in the evaluation phase, so I am trying to get the pros and

>> the cons figured out.  It does not sound like an SRDF standby can be opened

>> in read only, though I could be wrong about that.

>>

>>

>> On Mon, Jan 27, 2014 at 3:18 PM, Matthew Zito <matt_at_crackpotideas.com>wrote:

>>

>>> Well, so, this is the eternal debate, yeah?  Data Guard offers infinite

>>> flexibility, the DBA can control everything, it's storage agnostic, you

>>> have lots of knobs to twiddle, so on some levels that's perfect.

>>>

>>> On the flip side though, SRDF is application/OS agnostic.  Anything that

>>> gets written to any SRDF'ed LUN, regardless of database, filesystem, OS,

>>> version, etc. ends up on the far side.  Like magic.

>>>

>>> And SRDF is freakishly stable and mature.   It's been baked and stable

>>> for 15 years.

>>>

>>> So SRDF is often best when you might have different database

>>> technologies, or different OSes, and you care about 100% reliability.  It

>>> also removes responsibility from managing storage replication from the DBA

>>> team to some degree, since the array is responsible for pushing the bits

>>> around.

>>>

>>> With regards to the complexity - once you've done a reference

>>> architecture, gotten it working once, you just repeat it over and over

>>> again.  So that's a little bit of upfront effort, but I don't think in the

>>> long run it counts for much, especially compared with the care and feeding

>>> of DG.

>>>

>>> So I don't see it as an easy call either way - if you have a lot of

>>> strong oracle skills in-house and want the flexibility, DG is the way to

>>> go.  If you want to not have to deal with data protection and care about

>>> bulletproof reliability, or have a heterogenous environment, SRDF is great.

>>>

>>> Matt

>>>

>>>

>>> On Mon, Jan 27, 2014 at 4:08 PM, Andrew Kerber <andrew.kerber_at_gmail.com>wrote:

>>>

>>>> Yes, that makes sense.  I've been looking at the EMC web site, and

>>>> haven't really found anything definitive one way or another.  It really

>>>> sounds kind of tricky from what you are describing though, not sure I see a

>>>> real advantage over dataguard at that point.

>>>>

>>>>

>>>>

>>>>> On Mon, Jan 27, 2014 at 3:44 PM, Andrew Kerber <andrew.kerber_at_gmail.com

>>>>>> wrote:

>>>>>> Has anyone used EMC's SRDF with Oracle RAC 11gR2?  Any issues?  Does

>>>>>> it work with RAC?

>>>>>>

>>>>>>

>>>>>>

>>

>> --

>> Andrew W. Kerber

>>

>> 'If at first you dont succeed, dont take up skydiving.'

>>


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