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  1. WiredTiger
  2. WT-5071

dataPath increasing during hotbackup ("backup" cursor opening), index files cannot return to its size after restart

    • Type: Icon: Bug Bug
    • Resolution: Done
    • Priority: Icon: Major - P3 Major - P3
    • Backlog
    • Affects Version/s: 3.2.10, 3.6.8
    • Component/s: Backup, Btree, Checkpoints, Cursors
    • Environment:
      Using a replicated MongoD environment with one Primary, one Secondary, and one Hidden Secondary.
      CentOs 6

      doing the  hotbackup on the hidden node, and its dataPath is increasing, far lager than the primary and Sencondary node

       

      We do the  hotbackup on the hidden node, and its dataPath is increasing, far lager than the primary and Sencondary node  during hotbackup. 

       

          s->open_cursor(s, "backup:", NULL, NULL, &c);

         while( (ret = c->next(c)) == 0 && (ret = c->get_key(c, &filename)) 

         {

             copy files to slow disks

          }

          close_cursor(c )

       

      these files becomes larger during hotbackup:

           journal files,

           collection files,

            index files .

      we restart the hidden node when hotbackup ended, journal and files collection files can decrease to the size  the primary,  but the index files still so large 

      the process of hotbackup time is very long (sometimes about sevral hours to more than 20 hours) , because size of the data is large and we backup to very slow disks

       some instances  abort the disk of the datapath:
      Primary                    135G 
      Secondary                133G
      Hidden                      334G
      ------
      Primary                    211G 
      Secondary                213G
      Hidden                      330G
      ------
      Primary                    183G 
      Secondary                194G
      Hidden                     416G
      ------
      Primary                  964G 
      Secondary              964G 
      Hidden                    1.5T  
       
       
       

            Assignee:
            brian.lane@mongodb.com Brian Lane
            Reporter:
            244769542@qq.com li xiaojing
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              Created:
              Updated:
              Resolved: