I'm a DBA supporting both SQL 2000-2012, Oracle 11g, and Oracle 11g RAC.
IMO, Always On Availability Groups in SQL 2012 comes very close to the availability and scalability of RAC at much less cost in both dollars and complexity. You can scale out reads by querying against the mirrors, but you'd want to direct all DML to the primary server (SQL Server ...
dbms_scheduler.set_attribute is what you're looking for - it forces a job to run on a given node (specified by instance_id):
I can see why Oracle RAC can handle split brain and PXC cannot.
What separates them in their architecture and data storage. In what ways ???
All RAC Instances deal with only one set of database files
Each RAC Instance has its own Log Buffer and LGWR (Log Writer) process
Writes to any Oracle RAC instance, even on nodes that go down temporarily, ...
Although I haven't tried it, I would tend to suspect that you'll run into problems when your UNDO_RETENTION exceeds the length of time that Oracle maintains its SCN to timestamp mapping. If memory serves, that is roughly 1 week (well, if memory serves, it was 1 week in the 10g days and I'm not aware of anything that would have changed that in 11.2). I ...
Very high is a relative term that depends on perspective. You could mean 1 hour, 1 month, 1 year, etc. Assuming you mean something between one minute and one month, the answer will depend on how much undo is being produced and how much storage you have available. I haven't seen anything higher than two weeks.
Oracle automatically manages the undo space ...
There aren't any special considerations that need to be taken into account when setting up a RAC->No RAC Primary->Standby configuration.
In fact, there's a White Paper written by Oracle which explains the setup.
The Oracle documentation is here.
We can change IP address of public and private interfaces in the Oracle RAC environment using the Oracle supplied tool called OIFCFG(Oracle Interface Configuration). Here are some high level steps to do that.
Get new IP's from System Administrator
Stop all components
Check Actual Configuration
Delete previous RAC Interconnect Configuration
The database does not care about the IP addresses. Grid Infrastructure does. The method to change the IP addresses can be found in detail in the below MOS notes:
How to Modify Public Network Information including VIP in Oracle Clusterware (Doc ID 276434.1)
How to Modify Private Network Information in Oracle Clusterware (Doc ID 283684.1)
The output shows that your sessions use the "Thin" driver (JDBC Thin Client), which is incapable of using TAF.
Transparent Application Failover
Transparent Application Failover (TAF) is a feature of the Java
Database Connectivity (JDBC) Oracle Call Interface (OCI) driver.
Sometimes the JDBC OCI driver is also called as the "Thick" ...
Afer checking that you are indeed on the correct database and if ASH- and AWR reports for both instances don't show any long running queries it's time to get in touch with your application developers. Try to find out which statement exactly is slown and why.
I had similiar issues with various applications and application environments and issues I ...
It is actual quite easy if you are obvious of some caveats:
configure your services to run on one node only: srvctl modify service -db $DATABASE -service $SERVICENAME -preferred $INSTANCE1 -available $INSTANCE2 -modifyconfig
wait for the sessions to wander to the node running $INSTANCE1. This may take some time, it's heavily dependent on the type of ...
This can be caused by the asm_diskgroups parameter. On older releases (like 11g), this was a typical problem. This parameter was automatically updated, except when a diskgroup was dropped, then its name was not removed from the parameter values.
You can check this if you have access to MOS:
Dropped Diskgroup Still Existing in ASM spfile (Doc ID 2241177.1)
If you miss the '+' sign, there will be several scenarios:
db_create_file_dest is set and points to ASM (i.e: +DATA):
The database will take 'DATA' as an alias and will create ASM file on the destination associated with the 'DATA' alias that will be located at the ASM +DATA root directory.
db_create_file_dest is set and points to filesystem:
It should be ...
Up to 11g I know Oracle used the local OS time as the system time in a RAC environment, and I never heard that it changed so I'm comfortable saying it's still in place.
You would sync all the servers together typically using NTP or another solution to ensure the time sync. Usually if your servers local time is out of sync even by 30 seconds or so, you ...
A better comparison of AlwaysOn would be Oracle's Data Guard feature. Active-Passive clustering. (yes, you can read from standby, but it is read only, so still only one node is active")
Oracle RAC is a completely different animal, and active-active clustering. I did not see any moves if Microsoft will ever want to implement that.