Re: About the relation between fragmentation of file and VACUUM

On Dec 1, 2005, at 00:50, Tatsumi Abe wrote:

> However, In my current environment I can't stop PostgreSQL and cancel
> fragmentation.
>
> Could anyone advise some solutions for this fragmentation problem
> without stopping PostgreSQL ?

This is somewhat of an aside and intended just as a helpful suggestion
since I've been in this spot before: if you have this kind of uptime
requirement the first project to work on is getting the environment to
the point where you can take out at least one database server at a time
for maintenance.  You're going to be forced to do this sooner or later
- whether by disk failure, software error (Pg or OS), user error
(restore from backup) or security issues (must patch fixes).

So disk fragmentation is a great thing to worry about at some point,
but IMHO you've got your neck under the guillotine and worrying about
your cuticles.

I've heard the arguments before, usually around budget, and if the
company can't spend any money but needs blood-from-stone performance
tweaks, somebody isn't doing the math right (I'm assuming this isn't
running on a satellite).  Plus, your blood pressure will go down when
things are more resilient.  I've tried the superhero thing before and
it's just not worth it.

-Bill
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