[horde] horde_dns.cache on shared medium

[cheese at nosuchhost.net]

hi all,

we have the following situation:
several hosts with horde installed (horde01-04) which share a common 
directory via dns (conf.php:$conf['tmpdir'] = '/mnt/phptemp/';).

sometimes we have all four hordes segfaulting at the same time.
removing thme file /mnt/phptemp/horde_dns.cache settles that problem. a 
fresh file gets created and all seems ok again.

our questions:
*) is it OK to share $conf['tmpdir'] via NFS?
*) would it be OK to move horde_dns.cache to something unique, eg.: to 
/mnt/phptemp/horde_dns.cache.horde01 for the host horde01 ,...
*) would it be better to move that file to a local directory, eg /tmp/ ?
*) why is apache segfaulting which is quite harsh?

yours
josef