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  1. Solution Center
  2. SOL-105

Free database disk space (filesystem)

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    • Type: How To
    • Status: Obsolete
    • Affects Version/s: EXASolution 4.1.0, EXASolution 4.2.0
    • Fix Version/s: None
    • Component/s: EXAoperation
    • Labels:
      None
    • Solution:
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      This solution describes how to calculate free database disk space on filesystem based databases.
      Therefore you need in general:

      • data disk size of all active nodes (d02_data or d03_data, depends on your system configuration)
      • number of active database nodes
      • "Runtime Disk Usage" of the database

      Database disk usage

      To get the current database disk usage (netto) within the database execute following SQL:

      select DB_FILE_SIZE
      from EXA_STATISTICS.EXA_DB_SIZE_LAST_DAY 
      order by 1 desc limit 1;
      

      Even if the file is not fully used (please refer to USE column of EXA_DB_SIZE_LAST_DAY table), the file won't be defragmented and shrinked. The free space will be used for storing of new persistent data, but cannot be provided for backups or temporary data.

      Redundancy

      To provide a failover mechanism, every node stores his own and another nodes data file. This is the so called “Redundancy”. A Level-2 Redundancy enables the cluster nodes to restore all data of the failed node on the standby node. The standby node stores no data until it's pushed in during a failsafety: if a node fails, for whatever reason, the database performs a controlled shutdown and restarts itself with the pushed in standby node.

      Runtime Disk Usage

      Runtime Disk Usage displays the sum of

      • Data
      • Redundancy
      • Backups and
      • Temporary files

      Calculation of free space

      1. Get total node disk space


        Your system may have a separate data disk "d03_data"

        Name Type Size RAID Encryption Devices Free SW RAID State Mount Count Next Filesystem Check on Boot Expiration Date
        d02_data Data 4894GiB None None Default 2322.9GiB None 3/36 Mon Sep 29 12:21:48 2014
      2. Sum total disk space of all active nodes
        Assuming your cluster has 10 active database nodes:
        "Number of active Nodes" * "Disk Size" = " Total cluster disk space"
        -> 10 * 4894GB = 48940GB
        
      3. Get database space usage


        -> Note down the"Runtime Disk Usage"

      4. Calculate free database disk space
        "Total cluster disk space" - "Runtime Disk Usage" = "free database disk space"
        -> 48940GB - 27155.899GB = 21784.101GB
        
      Show
      This solution describes how to calculate free database disk space on filesystem based databases. Therefore you need in general: data disk size of all active nodes (d02_data or d03_data, depends on your system configuration) number of active database nodes "Runtime Disk Usage" of the database Database disk usage To get the current database disk usage (netto) within the database execute following SQL: select DB_FILE_SIZE from EXA_STATISTICS.EXA_DB_SIZE_LAST_DAY order by 1 desc limit 1; Even if the file is not fully used (please refer to USE column of EXA_DB_SIZE_LAST_DAY table), the file won't be defragmented and shrinked. The free space will be used for storing of new persistent data, but cannot be provided for backups or temporary data. Redundancy To provide a failover mechanism, every node stores his own and another nodes data file. This is the so called “Redundancy”. A Level-2 Redundancy enables the cluster nodes to restore all data of the failed node on the standby node. The standby node stores no data until it's pushed in during a failsafety: if a node fails, for whatever reason, the database performs a controlled shutdown and restarts itself with the pushed in standby node. Runtime Disk Usage Runtime Disk Usage displays the sum of Data Redundancy Backups and Temporary files Calculation of free space Get total node disk space Your system may have a separate data disk "d03_data" Name Type Size RAID Encryption Devices Free SW RAID State Mount Count Next Filesystem Check on Boot Expiration Date d02_data Data 4894GiB None None Default 2322.9GiB None 3/36 Mon Sep 29 12:21:48 2014 Sum total disk space of all active nodes Assuming your cluster has 10 active database nodes: "Number of active Nodes" * "Disk Size" = " Total cluster disk space" -> 10 * 4894GB = 48940GB Get database space usage -> Note down the"Runtime Disk Usage" Calculate free database disk space "Total cluster disk space" - "Runtime Disk Usage" = "free database disk space" -> 48940GB - 27155.899GB = 21784.101GB
    • Category 1:
      Cluster Administration - Cluster Management
    • Category 2:
      Cluster Administration - DB Instance Management

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            • Assignee:
              CaptainEXA Captain EXASOL
              Reporter:
              CaptainEXA Captain EXASOL
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