Comments

• Navin_C Vertica Customer ✭

  September 2014

  Hi Sunny,
  
  K safety factor is implemented on database level. Its a database property and not a cluster property.
  If you have two databases existing on same cluster, one can have k-safety as 1 and other can have k-safety as 0
  k-safety is implemented while creating databases. If you have created a database from admintools, at the time of creation, it will ask you db_name --> password --> k-safety value(0/1/2) in this sequence.
  
  It seems you have kept the k-safety value as 0 at the time of database creation, so you are getting this warning.
  If I am not wrong this warning must popup every time you log into vsql tool.
  
  Its not that the database will function improper if k-safety is 0, it only that, if a node goes down out of three nodes then your database will go down.
  
  Actually it not a thumb rule or any default, that a 3 node cluster will be k-safe 1, it will always be k-safe 0 for a database by default unless you specify a database to be k-safe 1 at creation time.
  
  How do we make it K-safe 1 after database is deployed:
  
  you can use vertica function
  
  MARK_DESIGN_KSAFE
  
  A few notes about this function:
  1. Lets say you had a table when database was k=0 , so there was one copy of data on all nodes and there were no buddy projections . Suppose you run the above function, the function will fail giving error message saying this projection does does not qualify with k=1 as it does not have a buddy projection and so the database cannot be set to k=1.
  2. This function does not change the existing schema of database top qualify for k=1
  
  Hope this helps.
  NC
  
  

  0