Re: dirty_ratio & dirty_background_ratio settings with huge memory - Mailing list pgsql-general

pinker wrote:
> I've got cutomer with really huge RAM, now it's:
>              total       used       free     shared    buffers     cached
> Mem:       3102111    3052596      49515     208801        992    2961185
> -/+ buffers/cache:      90418    3011693
> Swap:         8191          1       8190
> 
> (free -m)
> 
> and before it was twice more (6TB).
> 
> and trying to figure out how to set dirty_ratio & dirty_background_ratio
> parameters. Even for normal sized server those default sizes are to high,
> but now would be ridiculously huge, respectively 1,24TB and 300GB. 
> I'm thinking about 1 percent for dirty_ratio and not using
> dirty_background_ratio because it's not possible to set it below 1% but to
> set dirty_background_bytes instead to about 1-2GB.
> Maybe someone has got other experience with RAM of this size and those
> settings?

Yes, you should set vm.dirty_background_bytes and vm.dirty_bytes
and not use the *_ratio settings.

2 GB for vm.dirty_background_bytes and 1 GB for vm.dirty_bytes sounds fine.

Yours,
Laurenz Albe
-- 
Cybertec | https://www.cybertec-postgresql.com