freebsd stable - Mar 2008 - gjournal....

Hi folks;

Wondering about the various pros and cons of using the "gjournal" GEOM
provider... and if you can "promote" and existing system using it, or
whether you need to build something anew.

The scenario is a fairly busy and large system with PostgreSQL database data
on it.  The data is currently on a 2-disk gmirror pair to provide data
safety in the event of a disk failure.

I am using softupdates right now.

If I'm reading the docs correctly, I can't put gjournal in use on the
existing filesystem, and need to effectively build a new disk structure then
copy over the data onto it.

Can you boot from a gjournal'd root? 

Ideas please, pros and cons of the various alternatives, etc..... thanks!

--
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* Karl Denninger <karl@denninger.net> [080329 20:10]
wrote:
> Hi folks;
> 
> Wondering about the various pros and cons of using the "gjournal"
GEOM
> provider... and if you can "promote" and existing system using
it, or
> whether you need to build something anew.
> 
> The scenario is a fairly busy and large system with PostgreSQL database
data
> on it.  The data is currently on a 2-disk gmirror pair to provide data
> safety in the event of a disk failure.
> 
> I am using softupdates right now.
> 
> If I'm reading the docs correctly, I can't put gjournal in use on
the
> existing filesystem, and need to effectively build a new disk structure
then
> copy over the data onto it.
> 
> Can you boot from a gjournal'd root? 
> 
> Ideas please, pros and cons of the various alternatives, etc..... thanks!
> 
If you're using a database then it shouldn't matter what meta data
provider you use "all that much" with the exception of temporary
tables.

Basically, SU and gjournal both provide for meta data consistency,
something that a database rarely needs as it rarely creates/deletes
files often.

-- 
- Alfred Perlstein