Migrating a Database to an Exadata Machine

We have been migrating our databases from the non-Exadata servers to the Exadata Database Machine using the “RMAN 11g Duplicate standby from Active database” command, to create the standby databases on the Exadata machine. Below are the steps which were performed for these successful migrations. Assumptions Here we assume that the following tasks has been […]

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How important is a Disaster Recovery site for you?

I regularly read threads on the oracle-l mailing list, and occasionally feel very tempted to reply to one. Just recently I saw one that I liked a lot. It is specifically about using an Oracle Database Appliance (ODA) as a Disaster Recovery (DR) solution for an Exadata system. The Exadata configuration was not specified, I assume it was a smaller (eighth rack/quarter rack) configuration.

There were lots of arguments pro and against that Exadata->ODA architecture, (more...)

Database Shutdown With crsctl

I noticed something for the first time tonight when I was playing around in the Enkitec lab – something that I have been doing wrong for a while.  When working in the lab, I often rely on the crsctl command to shut down the entire cluster stack for me.  It’s really easy to use “crsctl stop cluster -all” followed by “dcli -l root -g ~/dbs_group /u01/app/11.2.0.4/grid/bin/crsctl stop crs” to get everything down (more...)

Cellcli can lie to you…

Yes that is true, i said it, cellcli can lie to you there are some special cases were the output of cellcli is not the reality and you should double check it’s output with your standard OS tools. So this the output if dcli calling cellcli on an Exadata rack from an client:

[root@dm01db01 ~]# dcli -g cell_group -l root cellcli -e list cell attributes cellsrvStatus,msStatus,rsStatus
dm01cel01: running       running         running
dm01cel02: running       running         running
dm01cel03:  (more...)

SCAN VIP Troubleshooting

We had a client that was running into a strange issue on their Exadata where new connections coming in through the SCAN were failing.  After doing some troubleshooting, it was discovered that it was related to one of the SCAN listeners not properly accepting requests from new sessions.  The VIP and listener were running, and everything looked normal.

We had the following SCAN setup:

SCAN VIP # VIP IP
1 172.25.2.70
2 (more...)

Use DCLI to check #em12c agents on Exadata – all at once

For all the benefits of Oracle Enterprise Manager 12c (OEM), there is one draw back when using OEM with Real Application Clusters or Exadata…. checking the status of the EM Agent on each node.  When a node is bounced, some times the EM Agent does not always restart.  When this happens on a single instance box or a RAC; normally you would have to check  each node individually and restart the agent.  (more...)

Troubleshooting Oracle DBFS mount issues

On Exadata the local drives on the compute nodes are not big enough to allow larger exports and often dbfs is configured. In my case I had a 1.2 TB dbfs file system mounted under /dbfs_direct/.

While I was doing some exports yesterday I found that my dbfs wasn’t mounted, running quick crsctl command to bring it online failed:

[oracle@exadb01 ~]$ crsctl start resource dbfs_mount -n exadb01
 CRS-2672: Attempting to start 'dbfs_mount' on 'exadb01'
  (more...)

Where does the Exadata storage() predicate come from?

On Exadata (or when setting cell_offload_plan_display = always on non-Exadata) you may see the storage() predicate in addition to the usual access() and filter() predicates in an execution plan:

SQL> SELECT * FROM dual WHERE dummy = 'X';

D
-
X

Check the plan:

SQL> @x
Display execution plan for last statement for this session from library cache...

PLAN_TABLE_OUTPUT
------------------------------------------------------------------------------------------------------------------------
SQL_ID  dtjs9v7q7zj1g, child number 0
-------------------------------------
SELECT * FROM dual WHERE dummy = 'X'

 (more...)

Meet “edb360″: a free tool that provides a 360-degree view of an Oracle database

Besides been what I consider a horrendous color, “edb360” also stands for Enkitec’s “database 360-degree” view. Simply put: edb360 is a new free tool that provides a 360-degree view of an Oracle database.

What is “edb360“?

This “edb360” tool is the product of a collaborative effort of some very smart guys, and me. Special thanks to Frits Hoogland, Karl Arao, Randy Johnson, Martin Bach, Kyle Hailey, Tanel Poder, (more...)

Kdump to NFS in UEK (Solution)

I’ve previously written about a problem I encountered when kdump is configured to write to an NFS location with UEK (in Exadata software version 11.2.3.2.1). I’m please to report that the root cause of the problem has been identified and there is a very simple workaround.

There were some frustrating times working this particular SR, the most notable being a response that was effectively, “It works for me (and so I’ll (more...)

Evènement : Sessions techniques Enterprise Manager

Deux sessions techniques autour d' Oracle Enterprise Manager sont planifiées prochainement :
- 15 mars : Middleware Management
- 2 avril : Database as a Service

Using SSD for a temp tablespace on Exadata

I seem to be getting a lot of surprising performance results lately on our X-2 quarter rack Exadata system, which is good – the result you don’t expect is the one that teaches you something new.

This time, I was looking at using a temporary tablespace based on flash disks (more...)

Exadata Optimizations and SQLTXPLAIN Courses

I will be delivering a couple of courses soon. One in January and the second in February. I will keep posting upcoming Training and Conferences on a new link at the right margin of this blog.

Exadata Optimizations Jan 13-14

This 2-days “Exadata Optimizations” course is for Developers (more...)

Exadata Storage Server Version 12.1.1.1.0 Released

Oracle has released the much-anticipated version of cellsrv compatible with Oracle Database 12.1.0.1 (patch #16980054). Before thinking about upgrading, read MOS note #1571789.1 carefully.  Unless you are planning to run database 12c on your Exadata, it would be advisable to continue down the 11.2 branch (more...)

Exadata x4 High Performance Disks

As I see, the data sheet of Exadata x4-2 says Oracle used 10.000 RPM disks for high performance. You probably know that Exadata provides 2 alternative configurations for hard disks. You may pick high performance (but low capacity) disks, or you may pick high capacity (but low performance) disks. (more...)

To DMA, Or Not To DMA

Exadata is a different system for a DBA to administer. Some tasks in this environment, such as running the exachk script, require root O/S privileges. This script can be run by the system administrator, and this will be the case if you are managing Exadata as a DBA. However, a (more...)

Annonce : Oracle Exadata Database Machine X4-2

L'annonce officielle de l'  Oracle Exadata Database Machine X4 a été faite lors de Cloud World à Sao Paulo du mercredi 11 décembre.
Retrouvez toute les informations sur http://www.oracle.com/us/products/database/exadata/database-machine-x4-2/overview/index.html 

Oracle Announces Exadata X4-2

Today, Oracle announced the Exadata X4-2 model.  The X4 has some considerable improvements, namely:

  • 12-core Intel Xeon e5-2697 CPUs, up from the 8-core models found in the X3-2 (hello, database licenses!)
  • 256GB RAM per database server, upgradeable to 512GB
  • 96GB RAM per storage server
  • 800GB Sun Flash F80 cards (more...)

Counting rows fast

A friend of mine asked me last night basically this: “How is that SQLTXPLAIN counts rows?”. In particular, he was referring to the use of the SAMPLE clause of the SELECT statement. Look at this SQLT’s log piece:

SQL_ID a9x1kc4ymyhkz
--------------------
SELECT /*+ FULL(t) PARALLEL */ COUNT(*) * 1e4
 (more...)

Exadata MAA Presentation – Oracle Day 2013 Istanbul

Exadata Maximum Availability Architecture from Yunus Emre Baransel