Check all farsync feature of 12c On 18 Nov 2014 20:18, "Mark W. Farnham" <mwf@xxxxxxxx> wrote: > This could be useful, for example, if standby #1 is local campus active > dataguard (or cloned) on a separate machine with a second network so the > work of forwarding the archived redologs is up to the (possibly remote) > standby machine for all of storage, network consumption, and cpu cycles. > > > > That could give you near real time currency locally and consume less > production cpu and network bandwidth on the machine(s) hosting the primary. > > > > I’d say different things can go wrong rather than more things that can > break. > > > > I have never measured the cpu and network cost of multiple arch_dest > definitions, and of course that would vary according to both your exact > load and your exact hardware. Whether or not license cost is an issue will > vary by topology and contract, but often it is not cost effective to burn > fully licensed cpu when other cpus could be doing the work, and especially > if the extra network bandwidth consumed burns production cpu cycles due to > spin waits. > > > > Without a detailed knowledge of service level requirement for the primary, > reporting for the first standby, and recoverability overall it is > impossible to know whether this topology would be good for a given customer. > > > > It sounds as if your data center has many customers. Whether internal or > external, there is a non-zero value to having everyone do things the same > way. Of course that is subject to still meeting service level requirements, > off-loaded reporting requirements, and recoverability requirements. > > > > Good luck! > > > > mwf > > > > *From:* oracle-l-bounce@xxxxxxxxxxxxx [mailto: > oracle-l-bounce@xxxxxxxxxxxxx] *On Behalf Of *Dba DBA > *Sent:* Tuesday, November 18, 2014 11:42 AM > *To:* ORACLE-L > *Subject:* Cascading Physical Standbys? > > > > I am not sure what the official term is. Its when you have > > > > Primary -> Standby -> Standby > > DB Version 11g and up. > > > > I work in a large data center. I was talking to another DBA and one of her > customers is doing this. I asked her why we would do this intead of just > using 'multiple arch_dest' locations then write the archive logs to separe > LUNs that under the surface map to separate RAID Groups. Little more work > up front for storage, but when its done its done. > > > > I see a cascading DB as more stuff that can break. The rationale I got is > that > > > > Standby #1 is for report and that Standby #2 is for DR. However, if > standby #2 is not current, then standby #3 is current. > > > > Anyone ever set this up before? I am just looking for rationals for doing > this. I am likely missing something. >