zhuhair
04-02-2005, 08:41 AM
Pls find below the excerpts from an article, which I feel would be useful...
Earthquake
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The raised floor greatly increases the difficulty of assuring or determining a seismic rating for a data center. Supporting equipment above the floor on a grid greatly compromises the ability to anchor equipment. Because each installation is different, it is almost impossible to test or validate the seismic rating of an installation. This is a very serious problem in cases where a seismic withstand capability is specified.
In and around Kobe Japan, during the great earthquake of 1995, data centers experienced an extraordinary range of earthquake damage. Many data centers which should have been operational within hours or days were down for more than a month when a large number of supposedly earthquake-rated raised floor systems
buckled, sending IT equipment crashing through the floor. Damaged equipment needed to be fished out and repaired or replaced in complex and time consuming operations.
During the World Trade Center collapse of 2001, nearby data centers which should have survived the tragedy were seriously damaged and experienced extended down time when impacts to the buildings caused raised floor systems to buckle and collapse.
A down time of 5 weeks as was typical near Kobe, corresponds to 50,000 minutes as compared with the 5 minutes per year of downtime required to achieve 5-nines reliability. This is 10,000 times worse than the 5-nines design value. If earthquake downtime is considered 10% of the availability budget, then the data centers near Kobe could not achieve 5-nines reliability unless an earthquake of that magnitude were to occur
only once every 100,000 years, which would not be a realistic assumption.
In areas which are subject to any earthquake activity it is unreasonable to expect 5-nines availability using a raised floor. Even an attempt to do so would be effectively unverifiable. This is one of the reasons why telephone central office facilities do not use raised floors. This is the single most compelling reason why raised floors are no longer desirable for high availability data centers.
Earthquake
'''''''''''''''''''''
The raised floor greatly increases the difficulty of assuring or determining a seismic rating for a data center. Supporting equipment above the floor on a grid greatly compromises the ability to anchor equipment. Because each installation is different, it is almost impossible to test or validate the seismic rating of an installation. This is a very serious problem in cases where a seismic withstand capability is specified.
In and around Kobe Japan, during the great earthquake of 1995, data centers experienced an extraordinary range of earthquake damage. Many data centers which should have been operational within hours or days were down for more than a month when a large number of supposedly earthquake-rated raised floor systems
buckled, sending IT equipment crashing through the floor. Damaged equipment needed to be fished out and repaired or replaced in complex and time consuming operations.
During the World Trade Center collapse of 2001, nearby data centers which should have survived the tragedy were seriously damaged and experienced extended down time when impacts to the buildings caused raised floor systems to buckle and collapse.
A down time of 5 weeks as was typical near Kobe, corresponds to 50,000 minutes as compared with the 5 minutes per year of downtime required to achieve 5-nines reliability. This is 10,000 times worse than the 5-nines design value. If earthquake downtime is considered 10% of the availability budget, then the data centers near Kobe could not achieve 5-nines reliability unless an earthquake of that magnitude were to occur
only once every 100,000 years, which would not be a realistic assumption.
In areas which are subject to any earthquake activity it is unreasonable to expect 5-nines availability using a raised floor. Even an attempt to do so would be effectively unverifiable. This is one of the reasons why telephone central office facilities do not use raised floors. This is the single most compelling reason why raised floors are no longer desirable for high availability data centers.