Speaking at BGOUG and UKOUG

It’s my pleasure to be speaking at BGOUG and UKOUG again this year.

The coming Wednesday 19th Oct, I’ll be speaking at the UKOUG Systems SIG event here in London (agenda). I’ll talk about Exadata implementations I did last year and issues I encountered. Also, things you need to keep in mind when you plan to extend the system, attach it to ZFS Storage Appliance or Exalytics.

Next is all time my favorite (more...)

OTN Appreciation Day: Oracle Data Guard Fast-Start Failover

Thank you, Tim, for the great idea.

There are so many cool database features one could spend weeks blogging about them.

A feature which I like very much is Oracle DataGuard Fast-Start Failover, FSFO for short.

Oracle DataGuard Fast-Start Failover was one of the many new features introduced in Oracle Database 10.2. It’s an addition to the already available DataGuard option to maintain standby databases. DataGuard FSFO is a feature that automatically, quickly, and (more...)

How to enable Exadata Write-Back Flash Cache

Yes, this is well-known and the process has been described in Exadata Write-Back Flash Cache – FAQ (Doc ID 1500257.1) but what the note fails to make clear is that you do NOT have to restart cell services anymore hence resync the griddisks!

I had to enable the WBFC many times before and every time I’d restart the cell services, as note suggests. Well, this is not required anymore, starting with 11.2.3. (more...)

Extending an Exadata Eighth Rack to a Quarter Rack

In the past year I’ve done a lot of Exadata deployments and probably half of them were eighth racks. It’s one of those temporary things – let’s do it now but we’ll change it later. It’s the same with the upgrades – I’ve never seen anyone doing an upgrade from an eighth rack to a quarter. However, a month ago one of our customers asked me to upgrade their three X5-2 HC 4TB units from (more...)

Grid Infrastructure 12c installation fails because of 255 in the subnet ID

I was doing another GI cluster installation last month when I got really weird error.

While root.sh was running on the first node I got the following error:

2016/07/01 15:02:10 CLSRSC-343: Successfully started Oracle Clusterware stack
2016/07/01 15:02:23 CLSRSC-180: An error occurred while executing the command '/ocw/grid/bin/oifcfg setif -global eth0/ eth1/' (error code 1)
2016/07/01 15:02:24 CLSRSC-287: FirstNode configuration failed
Died at /ocw/grid/crs/install/crsinstall.pm  (more...)

How to resolve missing dependency on exadata-sun-computenode-minimum

I’ve been really busy last few months – except spending a lot of time on M25 I’ve been doing a lot of Exadata installations and consolidations. I haven’t posted for some time now but the good news is that I got many drafts and presentations ideas.

This is a quick post about an issue I had recently. I had to integrate AD authentication over Kerberos on the compute nodes (blog post to follow) but had (more...)

Dead Connection Detection in Oracle Database 12c

In my earlier post I discussed what Dead Connection Detection is and why you should use it – read more here Oracle TNS-12535 and Dead Connection Detection

The pre-12c implementation of DCD used TNS packages to “ping” the client and relied on the underlying TCP stack which sometimes may take longer. Now in 12c this has changed and DCD probes are implemented by TCP Stack. The DCD probes will now use the TCP KEEPALIVE socket (more...)

Oracle Exadata X6 released

Oracle has just announced the next generation of Exadata Database Machine – X6-2 and X6-8.

Here are the changes for Exadata X6-2:
1) X6-2 Database Server: As always the hardware has been updated and the 2-socket database servers are now equip with latest twenty two-core Intel Xeon E5-2699 v4 “Broadwell” processors in comparison to X5 where we had eighteen-core Intel Xeon E5-2699 v3 processors. The memory is still DDR4 and the default configuration comes with (more...)

Oracle TNS-12535 and Dead Connection Detection

These days everything goes to the cloud or it has been collocated somewhere in a shared infrastructure. In this post I’ll talk about sessions being disconnected from your databases, firewalls and dead connection detection.


We moved number of 11g databases from one data centre to another.


Now probably many of you have seen the following error in your database alertlog “TNS-12535: TNS:operation timed out” or if you haven’t you will definitely see it (more...)

Exadata onecommand fails at cell disk creation

I was installing another Exadata last month when I got an error on create cell disks step. I’ve seen the same error before when I was extending two to three rack Exadata configuration but thought it was one-off.

The cell disk creation failed as below:

[root@exa01db01 linux-x64]# ./install.sh -cf Customer-exa01.xml -s 8

 Executing Create Cell Disks
 Checking physical disks for errors before creating celldisks.........................
 Restarting cell services....................................................

 Stopping the RS, CELLSRV,  (more...)

Issues with Oracle Direct NFS

This is a quick post to highlight two issues I had with Oracle dNFS. Both relate to wrong entries in the oranfstab file.

One might encounter ORA-00600 during database creation:

ORA-00600: internal error code, arguments: [KSSRMP1], [], [], [], [], [], [], [], [], [], [], []
ORA-17502: ksfdcre:3 Failed to create file /oracle/ORCL/database/ORCL/controlfile/o1_mf_%u_.ctl

This was caused by having a wrong entry in oranfstab (more...)

Come and hear me speak at UKOUG Tech 15

It’s this time of the year again when one of the biggest and last for the year Oracle User Groups is being held and that is UK Oracle User Group Conference.

I’m very grateful and proud that I’ll be speaking on this great conference, here are my talks:

Presentation Title: Oracle Exadata Meets Elastic Configurations
Description: With the release of Exadata X5 Oracle announced Elastic configuration to allow mixed number of db and cell (more...)

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...)

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...)

Introducing Oracle ASM Filter Driver

The Oracle ASMFD (Filter Driver) was introduced in Oracle Database and as of the moment it is available on Linux systems only.

Oracle ASM Filter Driver is a kernel module very much like the ASMLIB that resides in the I/O path of the Oracle ASM disks. It provides an interface between the Oracle binaries and the underlying operating environment.

Here are some of the features of ASMFD:

  • Reject non-Oracle I/O

The (more...)

Database system target in pending status for standby database in OEM 12c

That’s not really a problem but annoying issue I had with OEM 12c. Once a standby database is promoted, the database system for the same is showing as metric collections error OR Status Pending.

The standby database doesn’t need its own system since it will join the primary database system. The solution is to associate the standby database with the primary system and then remove the standby database system.

For example – we’ve got primary (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...)

Start of ‘ora.crf’ failed after update to DBBP7

This happened to me a month ago right after I applied DBBP7 on For some reason the ora.crf resource didn’t start automatically:

CRS-5013: Agent "ORAROOTAGENT" failed to start process "/u01/app/" for action "start": details at "(:CLSN00008:)" in "/u01/app/oracle/diag/crs/exa01db01/crs/trace/ohasd_orarootagent_root.trc"
CRS-2674: Start of 'ora.crf' on 'exa01db01' failed

Checking the trace file for more details you can immediately spot where the problem is:

2015-06-04 10:35:51.156513 :CLSDYNAM:3286230784: [  (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 exa01db02.local.net verified successfully
2015-07-01 12:31:03,713 [INFO  ][    main][     ValidationUtils:761] SUCCESS: NTP servers on machine exa01db01.local.net 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...)

MGMTDB not automatically created on Exadata X5 and GI

While deploying an X5 Full Rack recently it happened that the Grid Infrastructure Management Repository was not created by onecommand. The GIMR database was optional in and became mandatory in and should be automatically installed with Oracle Grid Infrastructure 12c release 1 ( For unknown reason to me that didn’t happen and I had to create it manually. I’ve checked all the log files (more...)