All, I am looking into clustering for exchange using active / passive setup. Have looked at both Google and Microsoft and have found an abundance of information to read and I don't think much is relevant to what I am trying to find out. Can anybody point me to a good reference site or book? Or can anybody tell the answers to the following question 1. does clustering have to be setup on SCSI? Or can you use IDE? 2. do the machines has to be identical in hardware setup (this I believe is true but am unable to find this in black and white) many thanks for your help Simon This email and any files transmitted with it are confidential and intended solely for the use of the individual or entity to whom they are addressed. If you have received this email in error please notify admin@xxxxxxxxxxxxxxx The views expressed in this email are those of the individual and not necessarily those of UK Data IT This footnote also confirms that this email message has been swept by SOPHOS AV for the presence of computer viruses. Web site: www.ukdatait.co.uk Registered Office: UK Data IT House, Shrub HIll Road, Worcester, WR4 9EF Registered Company Number: 3884834