I have an oracle database with no asm. If I shut down the database, move some of the dbf files to a location where I cannot preserve the timestamp on the files, then move them back... Will the database start up without any problem? I will not change anything in the contents of the dbf files nor the permissions.. only the OS timestamp will change. is this ok? Thanks!
Oracle does not care about the OS timestamp on data files. When it opens files it looks at the scn in all of the file headers and compares them to what is recorded in the control file. If all scn match, the database opens. If there is a mismatch between the scn of a file and that in the control file, it will throw an appropriate error. But none of this has to do with the OS time stamp on the file.
... if you want to be sure, you could also archive the files to the temporary location instead of moving them, eg. on Linux, just use
tar czf /path/to/tempLocation/databasefiles.tar.gz DBfile1 DBFile2 ... DBFileN
After doing your maintenance on their original storage, re-extract them with
tar xzf /path/to/tempLocation/databasefiles.tar.gz
The tar utility will preserve all metadata of files and directories, including timestamps. The simple gzip compression (as set with the "z" option to tar) will use less space on tempLocation, too.