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From: Axel Rau <Axel.Rau@chaos1.de>
To: Ivan Voras <ivoras@freebsd.org>
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Subject: Re: PostgreSQL 3.3 on gjournaled fs
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Am 09.08.2008 um 11:03 schrieb Ivan Voras:

> The question is - why do you need gjournal? PostgreSQL (and other  
> decent databases) does its own journaling (search for WAL), so using  
> it on a journaled file system doesn't do much.
I want to prevent from fsck on large filesystems after outage.
>
>
> If you really want it, it won't hurt you. Journal size needs to be  
> scaled based on your load. If you have constant writes you need a  
> larger journal. You need it to hold 20*(write_rate in MB/s)  
> megabytes. E.g. if your array does 100 MB/s, you need a 2000 MB  
> journal. This calculation is for default gjournal settings.
This is usefull info.
>
>
> You could put the journal on another drive or array for best  
> performance. (Of course, you could skip gjournal and put the WAL on  
> the other drive).
I have the latter, but intent to put this on gjournal too.

Axel
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