Hi folks,
Thinking about our disk requirements, three thoughts occur to me that I
thought I would checkpoint with our experts.
1. Jacek's latest calculations call for just over four thousand disks
to meet our I/O requirements. This is only 11% more than the 3600
disks we had planned for based on archive capacity needs. Note
that some of the capacity is to go to other things (e.g. images);
nevertheless, the disk is there to spread the database data
across. (See Document-1311 for details.) Thus, with the current
plan, meeting the I/O requirements does not result in a lot of
"free" space (of course, it's not really free ;-)
2. Originally, we budgeted a 20% overhead for RAIDing the disks.
However, we do not need to apply that factor to the 4000 disks
number we should still get the benefit of the performance
delivered by that extra 20% number of disks. (yes?)
3. If we account for the fact that the Data Access Center will also
be available to answer user queries of the type modelled, then we
actually have ~7000 disks available. Can we naively say that
preformance requirements per site go down by a 1/2?
cheers,
Ray
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