Vertica uses the concept of K-Safety for
failure recovery. The K value represents the maximum number of nodes in a
database that can fail and recover with no loss of data. In Vertica, the value
of K can be zero (0), one (1), or two (2). The Physical Schema design must meet
certain requirements. To create designs that are K-Safe, Vertica recommends
using the Database Designer.
To determine the number of nodes required to meet
your K-Safety needs, use the formula: K<N/2
where :
·
K is the K-Safety value.
·
N is the number of
nodes.
The value of K can be 1 or 2 only when the
physical schema design meets certain redundancy requirements. See Physical Schema. To create designs that are K-Safe, Vertica
recommends that you use the 
Database Designer.
Database Designer.
By default, Vertica creates K-Safe
superprojections when the database has a K-Safety greater than 0 (K>0). When
creating projections with the Database Designer, projection definitions that
meet K-Safe design requirements are recommended and marked with the K-Safety
level. Note the output from running the optimized design script generated by
the Database Designer in the following example:
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