When discussing Cary Millsap and his work (for example during this week’s user group presentation or when teaching courses), I’ve often said that I wish he was more widely known for one of my favourite pieces of work – the various Optimal Flexible Architecture documents and standards. I think one of the benefits of having worked with Oracle for a long time is that I remember pre-OFA days so I know precisely what problems OFA was designed to address.
Because Oracle eventually incorporated Cary’s ideas into the standard installation procedures, DBAs with less experience have become accustomed to the filesystem layouts, but I wish more of them had read the original standards or the installation manual or system admin guides. (It’s in different books on different versions and operating system ports).
Otherwise you get a variation on OFA that’s been picked up by looking at an OFA directory structure and modifying it slightly in ways that totally miss the point. Here are some filesystems I�ve come across recently
/myapp1/oradata/
/myapp1/oraindex/
/myapp2/oradata/
/myapp2/oraindex/
Which cause a few problems :-
1) We have large numbers of discrete filesystems for different applications. So if one application starts to run out of space, we might have free space kicking around on other applications� filesystems, but it’s unusable!
2) So people start putting files in inappropriate directories e.g. take an myapp1-related datafile and put it in /myapp2/oradata. Which will, of course end up being deleted by some enthusiastic sys admin when the other application reaches its end of life.
3) If we suddenly find that we need more index tablespace space and less data tablespace space, do we either a) take everything offline so we can steal from oradata to give to oraindex; or b) stick an index tablespace datafile in the oradata filesystem? If it’s b), why didn’t we just call them both oradata in the first place?!?!?
Then it gets worse.
Under the /myapp1/oradata mount-point, we have environment-specific directories
dev
test
support
But the relevant instance names are (made these up)
DOUGDEV
DOUGTST
DOUGSUPP
What exactly was the point in using anything but the SIDs to identify which database the files belonged to?
Trust me, there’s loads of this stuff. In 2005. I worked it out – the first OFA paper I saw was in 1993. How can people call themselves DBAs when they still can’t get it after 12 years?!!?I think I need a lie down …