Not sure about that - never ran Oracle on vmware before, but I wouldn't think it should require anything special. It sounds like the I/O to your SAN is just slower than the I/O to the internal disks, but you should run a 10046 trace (with waits) on both environments to confirm if that's really where the bottleneck is. Verify that both queries are using exactly the same explain plan first and then check the wait times for the db file scattered reads and also your average read times in v$filestat and/or statspack/AWR. You could also just bypass the database and check the I/O speed at the OS levels, e.g. by seeing how long it takes to copy a 500MB file or something like that. Regards, Brandon Privileged/Confidential Information may be contained in this message or attachments hereto. Please advise immediately if you or your employer do not consent to Internet email for messages of this kind. Opinions, conclusions and other information in this message that do not relate to the official business of this company shall be understood as neither given nor endorsed by it.