Oracle Data Guard 23c comes with many nice improvements for observability, which greatly increase the usability of Data Guard in environments with a high level of automation. For the 23c version, we have the following new views.V$DG_BROKER_ROLE_CHANGE This view tracks the last role transitions that occurred in the configuration. Example: SQL> select * from v$dg_broker_role_change; EVENT STANDBY_TYPE OLD_PRIMARY NEW_PRIMARY FS_FAILOVER_REASON BEGIN_TIME END_TIME CON_ID _____________ _______________ _____________ ..read more

Oracle Data Guard 21c came with a new command: prepare database for data guard with db_unique_name is {db_unique_name} db_recovery_file_dest_size is "{size}" db_recovery_file_dest is "{dest}" ; This command prepares a database to become primary in a Data Guard configuration. It sets many recommended parameters: DB_FILES = 1024 LOG_BUFFER = 256M DB_BLOCK_CHECKSUM = TYPICAL DB_LOST_WRITE_PROTECT = TYPICAL DB_FLASHBACK_RETENTION_TARGET = 120 PARALLEL_THREADS_PER_CPU = 1 STANDBY_FILE_MANAGEMENT = AUTO DG_BROKER_START ..read more

Short answer: yes. Let’s just see it in action. First, I have a Data Guard configuration in place. On the primary database, the current incarnation has a single parent (the template from which it has been created): SQL> select * from v$database_incarnation; INCARNATION# RESETLOGS_CHANGE# RESETLOGS PRIOR_RESETLOGS_CHANGE# PRIOR_RES ------------ ----------------- --------- ----------------------- --------- STATUS RESETLOGS_ID PRIOR_INCARNATION# FLASHBACK_DATABASE_ALLOWED CON_ID ------- ------------ ------------------ -------------------------- ---------- 1 1 ..read more

A month ago, I saw this article published on the AWS architecture blog: Disaster Recovery for Oracle Database on Amazon EC2 with Fast-Start Failover I love seeing people suggesting Oracle Data Guard Fast-Start Failover for high availability. Nevertheless, there are a few problems with the architecture and steps proposed in the article. I sent my comments via Disqus on the AWS blogging platform, but after a month, my comment was rejected, and the blog content hasn’t changed. For this reason, I don’t have other places to post my comment but here… The link to the setup procedure is from 2009. We ..read more

The video explains best practices and different failure scenarios for different observer placements. It also shows how to configure high availability for the observer. Here’s the summary: Always try to put the observer(s) on an external site. If you don’t have any, put it where the primary database is, and have one ready on the secondary site after the role transition. Don’t put the observer together with the standby database! Configure multiple observers for high availability, and use the PreferredObserverHosts Data Guard member property to ensure you never run the observer where the standb ..read more

Why is Fast-Start Failover a crucial component for mission-critical Data Guard deployments? The observer lowers the RTO in case of failure, and the Fast-Start Failover protection modes protect the database from split-brain and data loss ..read more

Are you attending OCW, and do you want to find me and know more about how to avoid downtime and data loss? Or how to optimize your application configuration to make the most out of MAA technologies? Or any database, or technology-related topic? Maybe you prefer just a chat and discussing life? Over a coffee, or tea? (or maybe beer?) This is where you can find me during OCW. Monday, October 17, 2022 6:30 PM – 10:00 PM – Customer Appreciation Event Where: Mandalay Bay Shark Reef This is an invitation-only event. If you are one of the lucky customers that possess an invitation, let’s meet there ..read more

Update PHP: Update WordPress: New content: It’s almost six months without blogging from my side. What a bad score! It’s not a coincidence that I’m blogging today during #JoelKallmanDay. A day that reminds the community how important it is to share. Knowledge, mostly. But also good and bad experiences, emotions… A bittersweet day, at least for me. On the bitter side: it reminds me of Joel, Pieter, and other friends that are not there anymore. That as a Product Manager, I have to wear big shoes, and it does not matter how good I try to do; I will always feel that it’s not good enough for the ..read more

Oracle advertises Far Sync as a solution for “Zero Data Loss at any distance”. This is because the primary sends its redo stream synchronously to the Far Sync, which relays it to the remote physical standby. There are many reasons why Far Sync is an optimal solution for this use case, but that’s not the topic of this post Some customers ask: Can I configure Far Sync to receive the redo stream asynchronously? Although a direct standby receiving asynchronously would be a better idea, Far Sync can receive asynchronously as well. And one reason might be to send asynchronously to one Far Sync memb ..read more

The answer is YES. In the following configuration, cdgsima_lhr1pq (primary) sends synchronously to cdgsima_farsync1 (far sync), which forwards the redo stream asynchronously to cdgsima_lhr1bm (physical standby): DGMGRL> show configuration verbose Configuration - cdgsima Protection Mode: MaxPerformance Members: cdgsima_lhr1pq - Primary database cdgsima_farsync1 - Far sync instance cdgsima_lhr1bm - Physical standby database cdgsima_lhr1bm - Physical standby database (alternate of cdgsima_farsync1) Members Not Receiving Redo: cdgsima_farsync2 - Far sync instan ..read more