[Dovecot] Dovecot,nfs or memory indexing

Hi,

I wonder if it's normal behaviour that indexes created in memory have long creation time. Other problem is that indexes created on nfs sometimes get crushed and I need to delete indexes in case of fetching mails ( I see mails on hd but when telnet on host and make stat I don't see any). Does version 1.1.x correct this errors ? And what is better to use : nfs or memory indexing ? Can someone point me adventages and disadventages of using both solutions?

Best regards,

Sebastian