Friday, 7 December 2012

Netbackup Important Terminologies -- Part 2

Major Daemons Running in Master/Media/Client

Master - 4 Daemons
           i) bprd       --  request daemon started during the system.
          ii) bpsched  -- schedule daemon
         iii) bpdbm    -- database manager started by bpsched
         iv) bpjobd    -- Job monitor daemon started by bpdbm
               bprd --> bpsched --> bpdbm --> bpjobd

 Media - 9 Daemons 
          i) bpcd   -- Backup Client (Since media itself is a client)
         ii) bpbrm -- Backup and restore daemon
        iii) bpdm  -- Backup disk manager
        iv) bptm   -- Backup tape manager
         v) ltid     -- Media manager daemon started during the system boot
        vi) avrd    -- Automatic Volume Recognition daemon
       vii) vmd    -- Volume Manager daemon 
      viii) tldd     -- robotic tape library daemon
        ix) tldcd   -- robotic tape library controller daemon

Client - 2 daemons  
        i) bpcd -- NB client daemon
       ii) bpbkar -- Daemon used to take backup images.

How Netbackup process works?
        There are 7 steps involve in NB
     In Master Server 

             bprd --> bpsched --> bpdbm --> bpjobd
        Step 1:
             *  When the daemon starts "bprd" on the master server start "bpsched" 
       Step 2:
             *  "bpsched"  calls bpdbm to check the policy for auto backup schedules 
                  "bpsched"  calls the child process to handle the backup
               "bpdbm"  calls the bpjobd to communicate with job catalog. 
         Step 3:
           "bpsched" child contacts the media server to start the bpcd
     In Media Server
             bpcd --> bpbrm --> bptm 
      Step 4: 
           * “bpcd” invokes  bpbrm
           * “bpbrm”  starts “bptm”  which requests a tape mount and spans a child process to communicate  with client. 
           * Vmd (Volume Manager Daemon) - manages the Volume catalog and handles media requests through out the course of the backup job.
           * “bpbrm”  contacts the client to start the “bpcd” in client. 
    In Client 
        Step 5:  "bpcd"  in the client starts the "bpbkar"
        Step 6:  "bpbkar" reads data from client
             * Communicates directly with "bpbrm" to send catalog meta data which is ultimately written to images catalog. 
             * Send the backup data stream to the "child bptm" process
       Step 7: 
             * The child bptm processes passes the data to the "parent bptm"
process which writes the data directly to the destination data.
What is Volume Group and Volume Pool?

Volume Pool
  • Is nothing but the “grouping of tape”. 
  • Meant  Volume/media/catridge/tape.
  • It is a Logical Set of Tape media/Volume.
  • If we want to use the newly introduced tape and to write to the data, it should be under one of the “volume pool” 
    We can we the Volume pools by the following ways. 
         In GUI,  Media and Device Management --> Media --> Volume Pools
         In CLI, #vmpool -list_all -bx
  root@MasterServer# vmpool -list_all -bx
  pool                    index   max partially full   description
  None                     0         0                the None pool
  NetBackup              1         0                the NetBackup pool
  DataStore               2         0                the DataStore pool
  CatalogBackup        3         0                NetBackup Catalog Backup pool
  SCRATCH_pool        4         0                for scratch media
  APPSERVER_LOGS    5         1                APP server logs
  DATABASE_LOGS     6         3                Database full
  WEBSERVER_FULL    7         1                Web server full

Volume Group
  • Is a Physical location  for a media. 
  • Manages a group of tape for purpose of admin actions that allows movement of tapes from slots to drive and vice versa.
  • All volumes in the VG should be the same media type. (HCART,DLT)
  • All volumes in a robotic library must belong to a volume group. You cannot add volumes to a robotic library without specifying a group.
  • We can view the Volume groups in 2 ways.
      i) In GUI, Media and Device management --> Media --> Volume Groups
      ii)In CLI, #vmquery -a |grep "media ID:"
   root@SS73VPBK01 # vmquery -a |grep "media ID:"
   media ID:              CLNU01
   media ID:              PL5001
   media ID:              PL5002
   media ID:              PL5003
   media ID:              PL5004
What are the Default Volume Pools?
     There are 4 volume pools created by default
       i) Netbackup --> new tapes are go to this pool after inventory
      ii) None (for cleaning tapes)
      iii) Datastore
      iv) Catalog backup

What is Scratch Pool ?
     Scratch pool is the manually created volume pool and following are the procedures of scratch pool 
     i) Expired Tapes (volumes) are automatically moved to scratch pool by netbackup.
    ii) If some other pools used for taking backup doesn't have any tapes available, it will take empty tapes from here.

What is Multistreaming and Multiplexing?

        i) Sends data from single client to multiple data drives. Normally used in high bandwidth environment.
      ii) Backups can be divided into streams. Different jobs in different tape.
     iii) Taken place in software level. 

      i) Send different  jobs/data into a single tape. Schedule level backup
     ii) It is very fast especially for small environment. 
    iii) Taken place in hardware level.


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