dovecot - Apr 2007 - Warning about NFS but using local fs for INDEX

I am playing around with dovecot and want to use local filesystem for indexing.
But whenever I open a new imap connection the following warning is shown:

Apr 30 10:14:42 beira dovecot: Mailbox indexes in /app/home/gasi are in NFS 
mount. You must set mmap_disable=yes to avoid index corruptions. If you're
sure
this check was wrong, set nfs_check=no.

/app/home is a NFS mounted filesystem, but I want dovecot to use 
/export/dovecot/gasi for indexing (See namespaces below).
I shurely can follow the hints(nfs_check=no), but I am not shure if I did
something wrong or maybe someday will change the configuration and forget to 
enable the nfs check.


dovecot version: dovecot-1.0-1.2.rc15.el5 on CentOS 5.0 (with all updates).

[root at beira etc]# dovecot -n
# /etc/dovecot.conf
syslog_facility: local6
login_dir: /var/run/dovecot/login
login_executable(default): /usr/libexec/dovecot/imap-login
login_executable(imap): /usr/libexec/dovecot/imap-login
login_executable(pop3): /usr/libexec/dovecot/pop3-login
mail_executable(default): /usr/libexec/dovecot/imap
mail_executable(imap): /usr/libexec/dovecot/imap
mail_executable(pop3): /usr/libexec/dovecot/pop3
mail_plugin_dir(default): /usr/lib/dovecot/imap
mail_plugin_dir(imap): /usr/lib/dovecot/imap
mail_plugin_dir(pop3): /usr/lib/dovecot/pop3
namespace:
   type: private
   separator: /
   location: mbox:~/Mail:INBOX=/var/spool/mail/%u:INDEX=/export/dovecot/%u
   inbox: yes
namespace:
   type: private
   separator: /
   prefix: #home-tmp/
   location: mbox:~:INDEX=/export/dovecot/%u
auth default:
   passdb:
     driver: pam
     args: imap
   userdb:
     driver: passwd

Herbert Gasiorowski wrote:
> I am playing around with dovecot and want to use local filesystem for 
> indexing.
> But whenever I open a new imap connection the following warning is shown:
> 
> Apr 30 10:14:42 beira dovecot: Mailbox indexes in /app/home/gasi are in 
> NFS mount. You must set mmap_disable=yes to avoid index corruptions. If 
> you're sure this check was wrong, set nfs_check=no.
> 
After adding a default - no namespace - mail location the warning no longer 
appears! Is it a bug or a feature: I thought defining a namespace with 
"inbox=yes" should be enought ..?

Here is the added line (from "dovecot -n"):

mail_location: mbox:~/Mail:INBOX=/var/spool/mail/%u:INDEX=/export/dovecot/%u
>..
> dovecot version: dovecot-1.0-1.2.rc15.el5 on CentOS 5.0 (with all updates).
> 
> [root at beira etc]# dovecot -n
> # /etc/dovecot.conf
> syslog_facility: local6
> login_dir: /var/run/dovecot/login
> login_executable(default): /usr/libexec/dovecot/imap-login
> login_executable(imap): /usr/libexec/dovecot/imap-login
> login_executable(pop3): /usr/libexec/dovecot/pop3-login
> mail_executable(default): /usr/libexec/dovecot/imap
> mail_executable(imap): /usr/libexec/dovecot/imap
> mail_executable(pop3): /usr/libexec/dovecot/pop3
> mail_plugin_dir(default): /usr/lib/dovecot/imap
> mail_plugin_dir(imap): /usr/lib/dovecot/imap
> mail_plugin_dir(pop3): /usr/lib/dovecot/pop3
> namespace:
>   type: private
>   separator: /
>   location: mbox:~/Mail:INBOX=/var/spool/mail/%u:INDEX=/export/dovecot/%u
>   inbox: yes
> namespace:
>   type: private
>   separator: /
>   prefix: #home-tmp/
>   location: mbox:~:INDEX=/export/dovecot/%u
> auth default:
>   passdb:
>     driver: pam
>     args: imap
>   userdb:
>     driver: passwd