DBA Best Practices

Arup Nanda has listed 5 DBA Best Practices

Recovery without UNDO Tablespace DataFiles

If you encounter a situation where an UNDO datafile is missing from a cloned database you can actually drop and recreate the UNDOTBS tablespace with
a) Shutdown immediate
b) Edit the init.ora to unset "undo_management=AUTO" {Oracle then ignores the setting of "undo_tablespace"}
c) Startup
d) Drop Tablespace UNDOTBS
e) Create UNDO Tablespace UNDOTBS datafile ...
f) Shutdown
g) Reset "undo_management=AUTO"
h) Startup Database

Programs that expect strings to be of a certain length !

Kevin Closson has posted on his blog a description of how the Oracle OUI encounters segmentation faults when trying to handle a very long Linux kernel name. Apparently, the OUI expects a length of not more than 30 characters but Kevin's team had been building Linux servers with longer names. Now, 30 characters is quite long enough, wouldn't you say ?
This is an example of a mismatch between two different program. Linux's "uname" call does not specify lengths for the uname structures but Oracle, going by experience from 100s of thousands of installations over the years, does not expect a name longer than 30 characters. I wouldn't fault Oracle !