Is there a way to disable lastlog ?

Hello !

We have a p570 system running AIX 5.3 and a telnet app. T
his system has an average off 2.000 users and 30.000 daily logins.
From time to time /etc/security/lastlog gets corrupted, and as result the login takes much longer than usual, sometimes several minutes.
I understand keeping track of all this users on a text file like lastlog is not an easy task for AIX. On the other hand, this system runs on a private network, and we have all login info in the app logs - so we don't really need AIX lastlog (we don't care about login attempts, too).

Is there a way to disable lastlog ? My guess is there isn't, as this would compromise AIX security - but I may be wrong. My other question would be: Is there a work around, like a login program replacement I could use to avoid this problem ? Any other suggestion ?

Thanks in advance,

Ronald