Issues with capacity planning pages on wiki

David Smith dizzyd at basho.com
Mon May 23 23:57:25 EDT 2011


On Mon, May 23, 2011 at 9:39 PM, Anthony Molinaro
<anthonym at alumni.caltech.edu> wrote:
>
>      Bitcask-Capacity-Planning     Cluster-Capacity-Planning   Reality
> RAM            34.9 GB                        34.9 GB             70 GB
> Disk          102 GB                          18.49 GB           341 GB
>
> So it looks to me like the numbers for RAM are about 1/2 of actual and
> the number for Disk are completely off, they are different depending on
> which page you look at on the wiki and vastly underestimate reality.

So RAM would require a little digging to figure out; disk is easier to
explain. The disk calculations do not take into account (as best I can
tell) the fact that bitcask is an append-only store and requires
periodic merging/compaction of the on-disk files. Thus, depending on
your merge triggers, more space can be used than is strictly necessary
to store the data.

D.

-- 
Dave Smith
Director, Engineering
Basho Technologies, Inc.
dizzyd at basho.com




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