Where the block location store in NAMENODE?

As i gone through some video of ITversity and some others doc also then i get to know FSimage only store Transition ID,Files and blocks name and permission,block mapping but not the block location.
Block location store only in RAM so apart from it doesn’t store anywhere with any file name?
IF no then my worrying is only that if Nmenode goes down due RAM issue or some other hardware issue then how it will recover the block location?

Block location will not be stored in fsimage.

Here is how restore happens

  • Namenode will start in safemode
  • fsimage will be restored (means file name and block ids will be stored in memory)
  • datanodes start communicating with namenode and they will actually fill the information of location
  • editlogs will be applied
  • Namenode will be out of safemode
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