Raw devices support in oracle db 12

According to some info from oracle support. Block devices will not be supported from next version of oracle – 12. Seems that oracle completely moves to ASM.

At this moment, oracle RAC 11.2 installer does not allow to use block/raw devices at installation phase. Later one can change location of voting disks and ocr to block devices. This will work on linux only.
note: it’s not possible to store voting files on both ASM and block devices

To move voting files use:
crsctl replace votedisk {+asm_disk_group | path_to_voting_disk}

For ocr:
ocrconfig -replace current_OCR_location -replacement new_OCR_location

Few notes on ‘Advanced Oracle Troubleshooting Seminar’ with Tanel Poder in Latvia.

On 21 November 2008, occurred long awaited event in Latvia – Advanced Oracle troubleshooting seminar with Tanel Poder (http://blog.tanelpoder.com/seminar/). The seminar was arranged by Affecto Latvia and Oracle University, lasted 2 days, and collected about 30-40 participants .

 Tanel started with the basics and continued with more advanced things touching practically every aspect of oracle troubleshooting. Advanced, in this context, means is what you do when all available oracle tools failed to show where the problem is. In this situation, Tanel proposing to troubleshoot oracle as standard UNIX application, perform traces and stack dumps, providing amazing information about what is what within stack trace.

 Another amazing thing is to see how very skilled professionals are working. I see this as very good opportunity to learn. Here he is showing fast and efficient way to deal with problems using his own custom build scripts. This approach is really accelerate process of diagnostics, especially when you are consulting professional with limited access to production servers and environment. But I think, this approach will be very useful for DBA as well, since for High Availability systems it’s very important to reduce impact on system as fast as possible, and for this purpose, systematic approach and planned environment is very important.

 I’ve personally very inspired by Tanel’s work and dedication and would like to thank you for great work and hope to see you in Riga again, with 3-5 extended seminar. Also, would like to thank Affecto Latvia and OU, that made this event possible, here, in Riga.

How to check free space in ASM

1. Connect to asm instance:

select name, state, total_mb, free_mb from v$asm_diskgroup;

NAME STATE TOTAL_MB FREE_MB
—————————— ———– ———- ———-
ORADATA MOUNTED 65536 53439

2. Using Grid Control

Go to asm host and select asm instance. Go Administration tab and input asm administration password:

3. Using ASMCMD tool

Please make sure to setup ORACLE_SID and ORACLE_HOME environment variables to ASM instance.

-bash-3.2$ asmcmd -p
ASMCMD [+] > du
Used_MB Mirror_used_MB
12011 12011
ASMCMD [+] >

or run

lsdg command

State    Type    Rebal  Unbal  Sector  Block       AU  Total_MB  Free_MB  Req_mir_free_MB  Usable_file_MB  Offline_disks  Name
MOUNTED  EXTERN  N      N        1024   4096  1048576     40960    37628                0           37628              0  ORADATA/
MOUNTED  EXTERN  N      N        1024   4096  1048576     32768    32675                0           32675              0  ORADATA1/

OUI starts and after prerequisites check, OUI crashes

From java trace file:

Unexpected Signal : EXCEPTION_ACCESS_VIOLATION (0xc0000005) occurred at PC=0x80D7A9C
Function=JVM_RegisterUnsafeMethods+0x18D
Library=C:\DOCUME~1\ab0959\LOCALS~1\Temp\OraInstall2008-03-05_09-25-08AM\jre\1.4.2\bin\client\
jvm.dll

Got this problem on client workstation (win2000prof). Initially we have attempted to start oracle iODS installation, but installer crasged just after prerequisites check by firt ‘next’ button pressed. Then I’ve checked if is possible to start 10.2.0.1 oracle client installation, but things got even worse, installer crashed just after prerequisites check completed with OUI wondow showed up for 1 sec.

What I have checked next with no luck:

  • user is in administrators group
  • path variable less than 1024
  • windows2000 sp4
  • installation folder is simple c:\install
  • we tested to install just after complete restart (no apps running)
  • no other oracle services running as system services
  • no problem with installation packages (tested on my own workstation)

Ive even suspected CPU issue, on this workstation new core2duo cpu (I still remember problems with installer on
Pentium4 😉

With help from oracle support, problem been resolved by removing unused oracle entries from windows registry (unregisted in oraInventory entries)

CAUSE: Windows registry seem corrupted on the Oracle branch

Oracle 32bin vs. 64 bit: quick test

What is overhead of using 64 bit addressing on oracle 64 bit systems comparing to 32 bit? For few days, I had test hardware in hands, to do quick check on this.

The quick test is on AMD Dualcore Opteron CPUs (HP BL685) running RHEL 5 and oracle 10.2.0.3

Server config:

4CPU

8GB total memory

2 sas hard drives in hardware mirror

Oracle configuration:

db_block_size 8K

db_cache_size 1200M

shared_pool_size 300M

Dedicated server. All other parameters are defaults.

Load configuration:

For load simulation, swingbench software from Dominic Giles is used (http://www.dominicgiles.com/swingbench.html)

Test: Order Entry application

Customers: 10M

Orders: 250K

Number of concurrent connections: 15 (from 1 client)

DB size: about 4GB

Test Results:

RHEL 5 and oracle 10.2.0.3 32bit

RHEL 5 and oracle 10.2.03 64bit

Conclusion:

AVG Response time

AVG. TPM

32bit

47

6768

64bit

53

6500

For this quick test, it seems that 32bit operations is little faster, this of course what it should be, just to prove on hands.

Note: this test intentions is more for load software familiarization, not academic purposes 🙂 To do more accurate testing required more time and testing, which is not currently available.

DBA future. Will we shift more to business?

For DBA. understanding business required for long time. Without this understanding hardly possible to tune application and db right. How to understand what exactly to tune – what is important to business? What backup and recovery strategy to develop? MTTR and MTBF? How company is confident in paying $500K only for oracle database enterprise edition? All this related to dba.

On the other hand, there are still loads of pure technical work to do, for example (what first comes to mind):

  • Developing and advancing backup and recovery strategy
  • Actual backups testing, restoring and testing
  • Different crash scenarios modeling and recovery testing
  • Recovery documentation and testing
  • Proactive monitoring and analysis
  • Moving data between test and development, sensual data scrambling
  • Maintaining security, patching, auditing, logs analysis
  • New features, new releases, new platforms, docs refresh, etc, etc

 

All this require time and professionals, and if more integration with business is needed, more resources is needed as well (simply add more resources – Grid Era :) This means, that pure technical DBA certainly will be needed. This is probably area for DBA assistants and regular DBAs. Seniors will probably do more business integration, or delegate this role to separate DBA.