Network-attached storage (NAS) devices have suffered from some serious flaws as far as Oracle is concerned. The Oracle database needs to be in near-constant contact with the database datafiles. Network glitches could cause the database to lose contact with those datafiles and cause the database to crash. Many DBAs find this unacceptable and won't even consider use NAS devices for their Oracle Databases. However, one of the more popular NAS vendors, NetApp now has some devices that work well with Oracle. Just make sure that your disk vendor will support Oracle on your NAS disk devices, otherwise, don't even bother with them.
Storage area networks (SAN) are much better and don't have the same problems. While technically on a "network," these devices should be placed on a dedicated switch for your SAN.
This was first published in April 2004