Re: [Exim] Re: Reliability of spool/delivery handling (Linux…

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Auteur: Sheldon Hearn
Datum:  
Aan: Suresh Ramasubramanian
CC: exim-users
Onderwerp: Re: [Exim] Re: Reliability of spool/delivery handling (Linux)?

On Mon, 27 Aug 2001 20:37:35 +0530, Suresh Ramasubramanian wrote:

> There _was_ a thread on postfix-users and elsewhere about softupdates having
> some issues with a large mail spool, IIRC (I don't run postfix - and one of
> my friends running postfix told me this after I suggested using
> softupdates).


This is FreeBSD-specific:

Unless you set the vfs.vmiodirenable sysctl(8) to 1 to turn on the
use of more aggressive buffer caching on directories and also use the
recently introduced UFS_DIRHASH kernel option, you're definitely going
to see performance degredation as your mail spool's size increases.

Using the split_spool_directory option will help, but ultimately, you're
going to want the VM and UFS subsystems helping you out.

Neither vfs.vmiodirenable nor UFS_DIRHASH are enabled by default,
because they are bad for low-memory systems. I think (but research is
advised) that low-memory in this case means less than 64MB.

Ciao,
Sheldon.