Author: Sheldon Hearn Date: To: Suresh Ramasubramanian CC: exim-users Subject: 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.
