Grid DBA

Databases Storage – The New Frontier As database and storage administrators and engineers, it is important to understand the effect that storage has on database performance. It is important to understand that databases are an extension of your storage and requires a holistic view when designing and managing solutions that use the database. This article gives an overview of the Oracle database storage landscape – past, present and future. It’s not meant as an in-depth technical treatment of the topic but opens the door for more discussion and engagement about database storage. Evolution Both storage and databases continue to evolve (albeit at different paces). About a decade ago the enterprise storage of choice was the Storage Area Network or SAN array. At about the same time the current release of Oracle was 10gR1, which introduced Automatic Storage Management (ASM), which provided mirroring and striping capabilities for data files. Database sizes were typically in the ...

Recently I was running some tests in my lab environment consisting of two Oracle 11.2.0.3 databases on separate RHEL 6.2 VMs. The databases were configured in a Data Guard configuration and used ASM as storage. However, I ran into an issue where my standby database was becoming out of sync with the primary database because the standby was out of disk space. At the time I couldn't request additional storage for my standby (that's what happens when you work at 1:00 am while everyone works normal hours) and I needed to complete my testing. The standby server had some NFS mounted shares that had plenty of space however. This is where social interaction is of benefit because I can recall having several discussions with fellow colleagues on twitter about choosing to use NFS as ASM devices and under what conditions one would choose such a route. Yury also wrote up a blog  post about it. This seemed like a good opportunity to test it out. Only this time I will be mixing ASM block de...

Just a quick note to self when adding datafiles located on ASM when using Data Guard. If the initialization parameter STANDBY_FILE_MANAGEMENT is set to AUTO then any datafile added on the primary database is automatically propagated to the standby site. Before adding the datafile on the primary site you need to verify that adequate disk space is available in the disk groups on both primary and standby. If not done, then your managed recovery will cease to operate thus causing risks to your disaster recovery database. Consider the example below. Datafile gets added on the primary database. ALTER TABLESPACE "FTSBCAUDIT" ADD DATAFILE '+DG_DATA' SIZE 8G REUSE AUTOEXTEND ON NEXT 100M MAXSIZE UNLIMITED Fri Oct 21 18:49:22 2011 Starting control autobackup Control autobackup written to DISK device         handle '/archivelogs/ftsora01/ftpprd/c-117026708-20111021-13' Completed: ALTER TABLESPACE "FTSBCAUDIT" ADD DATAFILE '+DG_DATA' SIZE 8G REUSE ...

ASM trace files begin with the "+" prefix.  On Unix/Linux I normally view database trace files using the more/less or vi/vim/view commands.  These commands and their variants however accept the "+" command as an option. Run 'man' on any of the commands to see what the "+" option does. Trying to use either of these commands may leave you a bit bewildered at first. [grid@oelgrid01 trace]$ more +ASM1_ora_15496.trc usage: more [-dflpcsu] [+linenum | +/pattern] name1 name2 ...   [grid@oelgrid01 trace]$ less +ASM1_ora_15496.trc   Missing filename ("less --help" for help) You have several other options to viewing these trace files.  Of course, you could do a tail/head against the file e.g  tail -50 +ASM_filename.trc .  But if the file was pretty big you would probably want to traverse back and forth.  For a small tracefile whose standard output fits on the screen you could just issue either of the following commands: cat +ASM_filename.trc c...

I started off my day somewhat later than planned, although I was up from 4:00 am.  Having been bitten by the dullness of previous day's keynotes I decided to skip this morning's session with John Fowler, Edward Screven and Mark Hurd.  My first session was at 11am so I decided to use the time and do some 'fun' stuff.  The DEMOgrounds was where I headed to try and bag some free swag before any cerebral activities.  There were quite a number of vendors displaying their wares - most of which were giving away some items in return for marketing opportunities.  By far the most popular giveaway item was iPads.  EMC claims that they are giving away an iPad every hour, with several other vendors attempting to follow suit.  I even had time to shoot some hoops in the Game Zone. After all the fun I sat in the the database general session with Andrew Mendelsohn - Why Standardize on Oracle Database 11g.  Andy kicked things off talking about new features in 11g...

So User Group Forum day has come and gone. The IOUG sessions were pretty good.  Naturally I was focusing on RAC, Grid Infrastructure/ASM etc.  My favourite session of the day was the Grid 2.0 session by Pythian's Alex Gorbachev - high entertainment value (oh yeah I learned stuff too). Running a close second to that was the Oracle Experts panel - pretty informative discussions but there wasn't enough time to answer all the questions. I also got to meet up with some pretty cool guys from twitterland - Chet (oraclenerd), Sunil Ranka and even ran into Alex  in between sessions. Chet and myself met up at the Welcome Keynote where we were expecting to have front-row seats - with our press/blogger pass and all.  Too late.  Safra Catz gave the opening welcome and introduced the HP keynote speakers.  This proved to be the most agonizing hour for most attendees including myself.  After what seemed like an eternity Larry did his own long pre-introductory ritu...

I haven't done a technical post in a while, so I thought I'd share some stuff I'd been working on recently. It may sometimes be necessary to migrate storage devices being used by a database and Oracle Clusterware.   This may be due to a SAN upgrade or simply moving between storage frames.   AIX provides a native command called migratepv which can handle the movement of logical volume groups and filesystems.   However, for Clusterware (OCR & Voting Disks), and ASM which reside on raw devices, a different method is required.   The ocrconfig and crsctl commands are the preferred methods of working with OCR and voting disk files.   Instructions on migrating AIX volume groups using migratepv   is beyond the scope of this article but you can check out this article by Chris Gibson for additional details http://www.ibm.com/developerworks/aix/library/au-aixstorage/ . This document will describe the steps used to migrate the following types of devices at...