Oracle ADG vs DG

Oracle ADG vs DG

其實(shí)ADG的實(shí)驗(yàn)自己早已做過，就是不知道是DG的升級(jí)版而已。

ADG: Active Data Guard

DG: Data Guard

What is the difference between DG and ADG ? 

From the docs: 
Oracle Data Guard ensures high availability, dataprotection, and disaster recovery for enterprise data. Oracle Data Guardprovides a comprehensive set of services that create, maintain, manage, andmonitor one or more standby databases to enable production Oracle databases tosurvive disasters and data corruptions. Oracle Data Guard maintains thesestandby databases as copies of the production database. Then, if the productiondatabase becomes unavailable because of a planned or an unplanned outage, OracleData Guard can switch any standby database to the production role, minimizingthe downtime associated with the outage. Oracle Data Guard can be used withtraditional backup, restoration, and cluster techniques to provide a high levelof data protection and data availability. 
Oracle dg保證高可用性、數(shù)據(jù)保護(hù)、企業(yè)數(shù)據(jù)的災(zāi)難恢復(fù)。Oracle dg提供一系列的綜合性服務(wù)，如一個(gè)或多個(gè)備庫(kù)的創(chuàng)建、維護(hù)、管理和監(jiān)控，使得生產(chǎn)庫(kù)從災(zāi)難、數(shù)據(jù)崩潰中得以恢復(fù)。Oracle dg維護(hù)這些備庫(kù)作為生產(chǎn)庫(kù)的副本。如果生產(chǎn)庫(kù)因計(jì)劃或非計(jì)劃的中斷，dg可切換任何一個(gè)備庫(kù)當(dāng)人生產(chǎn)庫(kù)的角色，最小化因中斷造成的宕機(jī)時(shí)間。DG也可用作傳統(tǒng)的備份、恢復(fù)、提供數(shù)據(jù)高可用和保護(hù)的集群技術(shù)。
So both DG and ADG provide those additional copiesof the database. Early DG versions provided that facility solely for disasterrecovery. Nowadays, there are many other things you can use DG for, eg, youcould backup the DG copy rather than the production database to ease resourceconsumption etc. 
因此DG和ADG都提供數(shù)據(jù)庫(kù)的附加復(fù)制。早期版本的DG只提供數(shù)據(jù)的災(zāi)難恢復(fù)?，F(xiàn)在你通過DG有很多其他的東西可以使用，如你可備份DG庫(kù)而不是生產(chǎn)庫(kù)來達(dá)到降低資源消耗的目的。
Where ADG offers more is that you can have thedatabase open for read-only (eg reports) whilst it is still being kept in syncwith your primary database. With normal DG, if you want it open read-only, youmust pause the sync process. 

ADG能提供更多的就是你能使DG庫(kù)以只讀狀態(tài)打開，同時(shí)DG庫(kù)保持和主庫(kù)的同步。對(duì)于普通的DG，你以只讀形式打開DG庫(kù)，必須暫停同步進(jìn)程。

What is the difference betweenADG and GoldenGate ? 

ADG maintains a physical copy of yourprimary database (that can be read by queries). You are100% positive that it and the primary are the same.

Goldengate replicates *changes* from yourprimary database to a secondary but quite separate copy of your database. This second copy might be a subset, or superset, or simply bedivergent from your primary. The advantage is that this secondarydatabase can be read-write...its really a *different* database into whichchanges are being pushed.