Hello,
I was also not able to use vi, and when I tried to telnet to the lpar, I received this error;
"cannot write to /var/adm/wtmp", but I managed to login.
I was not able to write to wtmp, and from errpt, I found these errors;
"Filesystem corrupted", "Filesystem recovery is needed" and the filesize for var/adm/wtmp was not increasing.
I ran an fsck test (online) on /var and it shows some inode errors that need to be fixed.
What I did was I ran fsck in maintenance mode (offline) by booting up from mksysb tape.
As of this morning, it looks okay
Thanks everyone!