Re: 21 terabytes at NYNEX

In article <4llm6j$2m1_at_gol2.gol.com>, John Durkin <yamanote_at_gol.com> wrote:
>mew_at_world.std.com (Michael E Willett) wrote:
>
>>In the April 22 WSJ article "Storage Devices Take Spotlight
>>in Computer Industry," Jerry Higgins, who manages a database
>>of 21 trillion bytes of data at NYNEX, says, "Computers are
>>becoming a sidelight to the data warehouses."...
>
>Although I respect the concept of 21 TB of storage, I would like to
>know how this backed up. With current technology, it sounds like a
>near impossible task, unless the 21 TB DASD is mirrored. Even then,
>at some point I assume a tape backup must be taken.

21 TB would not fit on most 32 bit UNIX servers. There is a 2 GB limit on file sizes and typically about a 1 K limit on the number of files open at once. This would most likely be a distributed design if it is using open systems. With many machines the backup is spread over many tape drives.

Also in data warehouses most of the data is read only. If the data is partitioned correctly only a small fraction of the change data is backed up.

>Or, does the concept of backup not exist for data warehouses? Of
>course it must, as these type of applications become more and more
>mission critical. I would like to hear from the storage gurus how
>massive amounts of DASD can be efficiently backed up and restored when
>necessary.

Hope this helps

Mark Rosenbaum				Otey-Rosenbaum & Frazier
mjr_at_netcom.com				Consultants in High Performance and
(303) 727-7956				Scalable Computing and Applications