Monthly Archives: July 2019

Understanding ZDLRA

Oracle Zero Data Loss Recovery Appliance (ZDLRA) deliver to you the capacity to improve the reliability of your environment in more than one way. You can improve the RPO (Recovery Point Objective) for your databases until you reach zero, zero data loss. And besides that, adding a lot of new cool features (virtual backups, real-time redo, tape and cloud, DG/MAA integration) on the way how you do that your backups (incremental forever), and backup strategy. And again, besides that, improve the MAA at the highest level that you can hit.

But this is just marketing, right? No, really, works pretty well! My history with ZDLRA  starts with Oracle Open World 2014 when they released the ZDLRA and I watched the session/presentation. At that moment I figure out how good the solution was. In that moment, hit exactly the problem that I was suffering for databases: deduplication (bad dedup). One year later, in 2015 at OOW I made the presentation for a big project that I coordinate (from definition implementation, and usage)  with 2 Sites + 2 ZDLRA + N Exadata’s + Zero RPO and RTO + DG + Replication. And at the end of 2017 moved to a new continent, but still involved with MAA and ZDLRA until today.

This post is just a little start point about ZDLRA, I will do a quick review about some key points but will write about each one (with examples) in several other dedicates posts. I will not cover the bureaucratic steps to build the project like that, POC, scope definition, key turn points, and budget. I will talk technically about ZDLRA.

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INDEX_BACKUP task for ZDLRA, Check percentage done

Quick post how to check and identify done for INDEX_BACKUP task in ZDLRA. In one simple way, just to contextualize, INDEX_BACKUP is one task for ZDLRA that (after you input the backup of datafile) generate an index of the blocks and create the virtual backup for you.

Here I will start a new series about ZDLRA with some hints based on my usage experience (practically since the release in 2014). The post from today is just little scratch about ZDLRA internals, I will extend this post in others (and future posts), stay tuned.

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Reimage ODA

The idea to reimage ODA is to refresh the environment without the need to jump from one by one to reach the last available version, or even rescue the system from S.O. failure/crash. The process to do a reimage can be check in the official documentation but unfortunately can be very tricky because the information (the order and steps) are not 100% clear. The idea is to show you how to reimage using version 18 (18.3 in this example), that represents the last available.

In resume the process is executed in the order:

  1. ILOM: Boot the ISO
  2. Prepare to create the appliance
  3. Upload GI and DB base version to the repository
  4. Linux: Create the appliance
  5. Firmware and patch
  6. Create Oracle Homes and the databases
  7. Finish and clean the install

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RMAN, Allocate channel, CDB, and CLOSE: bug

Allocate channel for RMAN is used in various scenarios, most of the time is useful when you use tape as device type or you need to use some kind of format. The way to do the allocation not changed since a long time ago, but when you run the database in container mode you can hit a bug that turns your channel unusable. I will show you the bug and how to avoid it with a simple trick.

This bug hit every version since 12 and I discovered it last year when testing some scenarios, but I was able to test and post just recently. It just occurs for CDB databases and exists just one one-off solution published for 12.2. But there is one workaround more useful and works for every version.

The most interesting part is that everything that we made until now when allocate channel will not work. You can search in all doc available for allocate channel since 9i until 19c the first thing that you made after open the run{} is allocate channel. This is the default and recommended in the docs: for 19c, 18c, and 9i.

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