As a response to my previous post about adding and dropping ASM disks with one command Emre Baransel asked a question as to whether it was more efficient or not to do it as one or two commands. It was easier to add a second post complete with screen shots rather than just a simple reply.
My test system was a 3.5Tb database spread across 10 512Gb luns.
The first choice was to add and drop in one command
One of the possibilities within ASM that is not widely documented is the opportunity to add disks, drop disks and set the rebalance power all in one command.
One might wonder when you might be both adding and dropping disks simultaneously from the same disk group. Recently we have been migrating to a new storage array and this command comes in very useful in that situation
On any HPUX (11:31) system where grid infrastructure has been applied with 2 software owners – in our case grid and oracle – oracle’s best practise for GI implementations – RAC or standalone systems.
The standard unix account we are using is , testuser (although in this case he is in the DBA group).
This user is a member of the following groups :
You may notice a large and growing trace file in diag dest which contains numerous lines starting with the phrase “NOTE: Unident of disk ” followed by a disk path.
Back in Nov 2011 I posted a question on the Oracle-L mailing group about my perception that ASM disk rebalances seemed to be required on DATA diskgroups in ASM (never FRA, presumably because the FRA had lots of similar sized objects (flashlogs archivelogs etc)) and even after rebalancing there seemed to be a permanent imbalance between disks of the same size. I was querying the effectiveness of the rebalancing operation.
For anybody who is interested in reading about optimizer statistics and gaining a clear understanding on what they can do and how they can be managed then I suggest reading the following two white papers
In my last post I talked about doing a lot of interview questions lately. I have been thinking of changing my standard set of questions anyway so I thought it would be a good idea to write about the questions I have been asking and the responses I get.
I have been doing a lot of interviewing recently and I have a set of questions which are quite generic but I like to use them to lead into areas where I can probe a bit deeper if the interviewee allows me to get that far by answering the question correctly in the first place.
Back in 2009 I posted a script which I found very useful to review ASM disks. I gave that post the low-key title of The ASM script of all ASM scripts. Now that script has been improved I have to go a bit further with the hyperbole and we have the The Mother of all ASM scripts. If it ever gets improved then the next post will just be called ‘Who’s the Daddy’.
The UKOUG have done really well in organising the next Database Server SIG. It is being held at the City of Manchester Stadium – the home of Manchester City. That is the group of players bought on the cheap and managed by Roberto Mancini into the best team in Britain as will be proved when we win the Premier League in April.
They have got two of the worlds’ top Oracle speakers on stage. Actually that is slightly incorrect. They have one of the worlds’ top Oracle speakers talking twice and me also on stage.
The agenda looks very strong