Backup to ZFS Storage Appliance Best Practices for Exadata Database Machine

I made a presentation called "Best Practices for Exadata Maximum Availability" at BGOUG autumn event last week. In addition to general Exadata best practices about backup&recovery, disaster recovery, RAC&ASM, corruption detection features; i reserved half of my time to speak about integration of Exadata and ZFS storage appliance for the best performance of database backup&recovery. This topic

How to rename ASM disk groups in Exadata

Deployment of Exadata requires you to generate configuration using Oracle Exadata Deployment Assistant (OEDA). Within the same the default  ASM disk groups names are DBFS_DG, RECOC1 and DATAC1. I usually change those to RECO01 and DATA01 as others doesn’t make sense to me and the only place where I find the default ones is on Exadata.

I had an incident last year where the Exadata deployed half way through and names were left by default (more...)

Oracle SPARC M7 Processor Breaks the “Sacrifice Performance for Security” Rule and Much More

Oracle Executive Vice President John Fowler used the occasion of Open World 2015 to introduce Oracle's SPARC M7 processor, the fastest in the world. Learn more ...

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Oracle 12c in-memory option and IO

This article is about the Oracle 12c in-memory option, and specifically looks at how the background worker processes do IO to populate the in-memory column store.

Hardware: Apple Macbook with VMWare Fusion 7.1.3.
Operating system: Oracle Linux 6.7, kernel: 3.8.13-118.el6uek.x86_64.
Database version: Oracle
Patch: opatch lspatches
19392604;OCW PATCH SET UPDATE : (19392604)
19303936;Database Patch Set Update : 12.1. (more...)

Direct path and buffered reads again: compressed tables.

In the previous post on the decision between buffered and direct path reads I showed the decision is depended on the version. Up to and including version the size of a segment needs to be five times small table threshold in order to be considered for direct path reads, and starting from the database starts considering direct path reads starting from small table threshold. The lower limit (more...)

How to move OEM12c management agent to new location

While working on another Exadata project recently I found that OEM12c agents on the compute nodes were installed on different locations on each of the three Exadatas. On one of them was under /home/oracle/agent, another one had them under /opt/oracle/agent and third one had them under /oracle/agent. Obviously this was not the standard and the agents had to be moved under /u01/app/oracle/agent. The only problem with that was that the three Exadatas were already discovered (more...)

Couchbase 4.0 and related subjects

I last wrote about Couchbase in November, 2012, around the time of Couchbase 2.0. One of the many new features I mentioned then was secondary indexing. Ravi Mayuram just checked in to tell me about Couchbase 4.0. One of the important new features he mentioned was what I think he said was Couchbase’s “first version” of secondary indexing. Obviously, I’m confused.

Now that you’re duly warned, let me remind you of aspects of (more...)

Direct path and buffered reads again.

Since the direct path feature for serial processes was discovered after it became available in Oracle (as far as I know, I haven’t checked Oracle 11.1), there have been a lot of blog posts on when this happens. A lot of these do not specify the Oracle version, which is a failure in my opinion. There are different decisions made in different versions.

The purpose of this blogpost is to show (more...)

OOW 2015: my presentation

I don’t have an official OOW presentation in the conference this year. However, I am presenting a session at the Oak Table World 2015 event behind held concurrently with OOW 2015. My topic is “Exadata Database Machine Security” and I plan to review some of the newest updates to security for the Exadata Database Machine engineered system.

As the website indicates, the event is completely free and there is no pre-registration or enrollment required–just show (more...)

Exadata X5 PDU – CLI already in use

Exadata X5-2 and X4-8B racks are delivered with the “Enhanced” PDU metering units connected via the Cisco switch. Although the documentation says they should have static addresses, they don’t. You need to configure them manually using serial console connection, this is described in my earlier post here.

However if you forget to exit the serial console connection to the PDU and then try to login using SSH later you’ll get the following message:

login as:  (more...)

Exadata Software is Released

Good new features announced, such as finding Flash Cache and Flash Log statistics on AWR, automatic ASM data redundancy check even shutting down a storage server by pressing the power button or through ILOM, preventing Flash Cache population in cell to cell rebalance, disabling SSH on Storage Servers and running CellCLI commands from Compute Nodes via new ExaCLI utility. Find details in the MOS

DBMCLI for Exadata Database Servers

Monitoring database servers for hardware failures in Exadata used to be an issue. We have CELLCLI for storage servers where we can make many administration tasks and set SMTP configuration to receive e-mail for hardware failures. For the DB servers we were able to configure SMTP Client on database server's ILOMs for email alerts but it was not a straightforward and easy configuration as we do in

Restoring a Database to a New Diskgroup

I had the pleasure of rebuilding an Exadata rack for a customer a while back, and it provided a pretty good refresher in backup and recovery for me.  As DBAs, we back up databases all the time, but the restores are performed much less frequently.  In the case of this rack, there were several databases across multiple ASM diskgroups.  One of the goals of the rebuild was to consolidate all of the databases into a (more...)

Shrink/Grow Exadata diskgroups

One of the important tasks that I foresee after an initial Exadata deployment is, mostly prior to DB in production, is to balance/resize the Exadata diskgroups (DATA & RECO).  Generally, the space is distributed as 80(DATA), 20(RECO) or 40(DATA), 60(RECO), depending on the database backup option you choose while deploying. In one of our Exadata setups, we don't need such a huge RECO size, hence, we shrunk the RECO size and increased the DATA diskgroup (more...)

Oracle 12 and latches

Oracle DBAs who are so old that they remember the days before Oracle 11.2 probably remember the tuning efforts for latches. I can still recall the latch number for cache buffers chains from the top of my head: number 98. In the older days this was another number, 157.

But it seems latches have become less of a problem in the modern days of Oracle 11.2 and higher. Still, when I generate heavy (more...)

Latest Release of Oracle Exadata Exachk and HealthCheck

Announcing the release of Exachk Version Exachk is a tool that is used to quickly determine the health of the entire Exadata infrastructure. Some of the key components that are checked include the database, cell servers and the network. This tool further reviews the configuration of the system and compares with the best practices. […]

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How long does a logical IO take?

This is a question that I played with for a long time. There have been statements on logical IO performance (“Logical IO is x times faster than Physical IO”), but nobody could answer the question what the actual logical IO time is. Of course you can see part of it in the system and session statistics (v$sysstat/v$sesstat), statistic name “session logical reads”. However, if you divide the number of logical reads by the total time (more...)

JSON support in Exadata and later

Some time ago Oracle announced that RDBMS has built-in support for JSON processing. A little later it was also mentioned that you have support for JSON in the Exadata storage servers for offloading. This is probably a lot more exciting to users of JSON than it is to me as I’m not a developer. However, whenever an announcement such as the one I’m referring to is made I would like to (more...)

Exadata’s onecommand fails to validate NTP servers on storage servers

This will be simple and short post on an issue I had recently. I got the following error while running the first step of onecommand – Validate Configuration File:

2015-07-01 12:31:03,712 [INFO  ][    main][     ValidationUtils:761] SUCCESS: NTP servers on machine verified successfully
2015-07-01 12:31:03,713 [INFO  ][    main][     ValidationUtils:761] SUCCESS: NTP servers on machine verified successfully
2015-07-01 12:31:03,714 [INFO  ][    main][     ValidationUtils:778] Following errors were found...
2015-07-01 12:31:03,714 [INFO  ][     (more...)

HAIP and Exadata

If you’ve run an exachk report, y0u may have seen the following message with regard to your databases:

Status Type Message Status On Details
FAIL Database Check Database parameter CLUSTER_INTERCONNECTS is NOT set to the recommended value db01:dbm011, db02:dbm012 View

This check is commonly seen when a database is created on Exadata without using the custom “Exadata” templates included with the database creation assistant.  These customized templates include a multitude of recommended parameter settings found in (more...)