[EMAIL PROTECTED] (R.S.) writes: > 1. DASD mirroring does not prevent you against errors in data. Errors > made by human, software bug, etc. > 2. Campus area seems to be too small to talk about serious DR > centre. Too short distance. Numerous disaster types could spread both > locations. > 3. There is no real protection (with excpetions to NORAD etc.) against > terrorist attacks. They can attack two locations at the same time, the > distance is irrelevant.
the early 80s ... there were some studies that chose 40 miles as a minimum number ... although you still have to look at common failure modes ... like 40 miles along the same river (flood plain) that would flood both locations. some places have extra redundancy with more than single replication. when we were doing ha/cmp product http://www.garlic.com/~lynn/subtopic.html#hacmp we coined the terms disaster survivability and geographic survivability http://www.garlic.com/~lynn/subtopic.html#available we talked to a number of operations about their experiences. one operation had carefully chosen a datacenter metropolitan bldg for (physical) diverse routes ... two different water mains on opposite sides of the bldgs, two power feeds from different power substations on opposite sides of the bldg., four telco feeds entering from four physical sides, from four different central offices. their datacenter went down when they had a transformer blow and the bldg. had to be evacuated because of PCB contaimination. some of this gets into other kinds of threat models ... misc. postings mentioning vulnerabilities, threats, exploits, fraud, etc http://www.garlic.com/~lynn/subintegrity.html#fraud and/or assurance http://www.garlic.com/~lynn/subintegrity.html#assurance ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [EMAIL PROTECTED] with the message: GET IBM-MAIN INFO Search the archives at http://bama.ua.edu/archives/ibm-main.html
