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From Batranut Bogdan <batra...@yahoo.com>
Subject Re: Nodetool clearsnapshot
Date Tue, 13 Jan 2015 14:30:23 GMT
OK Thanks,
But I also read that repair will take a snapshot. Due to the fact that I have Replication
factor 3 for my keyspace, I run nodetool clearsnapshot to keep disk space use to a minimum.
Will this impact my repair? 

     On Tuesday, January 13, 2015 4:19 PM, Jan Kesten <j.kesten@enercast.de> wrote:
   

  Hi,
 
 
  I have read that snapshots are basicaly symlinks and they do not take that much space. Why
if I run nodetool clearsnapshot it frees a lot of space? I am seeing GBs freed...  
 
 both together makes sense. Creating a snaphot just creates links for all files unter the
snapshot directory. This is very fast and takes no space. But those links are hard links,
not symbolic ones. 
 
 After a while your running cluster will compact some of its sstables and writing it to a
new one as deleting the old ones. Now for example you had SSTable1..4 and a snapshot with
the links to those four after compaction you will have one active SSTable5 which is newly
written and consumes space. The snapshot-linked ones are still there, still consuming their
space. Only when this snapshot is cleared you get your disk space back. 
 
 HTH,
 Jan
 
 
 

    
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