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Former Member

SAP HANA log backup frequency

Dear all,

we configured hana to use the hdbbackint backup interface.

Now we checked and have seen that over 650 logs are saved to the backup library one a day.

logs are genereated randomly but at least every 1 - 3 min.

Parameters are set :

log_backup_timeout_s = 900
log_segement_size_mb = 8 

i attached a screenshot of the log backup catalog.

do you know how we can handle that ? backups every 15 min should be ok i think.

greetings

oliver

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3 Answers

  • Best Answer
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    Former Member
    Dec 22, 2014 at 03:04 PM

    Hil Oliver,

    Which service generates the high amount of log-segments? You can use the below SQL Statement to aggregate the entries of the backup catalog or the backup.log to check that:

    service_type_name, count(*) from "PUBLIC"."M_BACKUP_CATALOG_FILES" a join "PUBLIC"."M_BACKUP_CATALOG" b on a.BACKUP_ID = b.BACKUP_ID where b.ENTRY_TYPE_NAME = 'log backup' and source_type_name = 'volume' and state_name = 'successful' group by service_type_name

    If it is the Statisticsserver, you can e.g. think about migrating to the embedded statisticsserver service (SAP Note 1917938) or increasing the log_segment_size_mb to 1024 Mb accordingly (which is the default for the indexserver). I think 8 Mb is the default log_segment_size_mb for the XSEngine which could be increased to 1024Mb too. It is recommended to stay with the default setting of log_backup_timeout_s (time until a not yet full log-segment is closed) as it has an impact on the Recovery Point Objective as outlined in the SAP HANA Administration Guide.

    Best regards,

    Michael

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    • Former Member Former Member

      Hello,

      it turned out that - on grouping the entries in backup.log by the service and filtering by states LogBackupStarted/LogBackupSuccess - a log backup is performed every 15 minutes. This is due to the log_backup_timeout_s which is reached as the log-segment was not full after this threshold exceeded.

      2015-01-15T14:45:07+01:00  P038871      14aedd63d50 INFO    LOGBCKUP state of service: indexserver, linux:31003, volume: 3, BackupLogStarted
      2015-01-15T14:46:20+01:00  P038871      14aedd63d50 INFO    LOGBCKUP state of service: indexserver, linux:31003, volume: 3, BackupLogSuccess

      >> 15 Minutes

      2015-01-15T15:00:07+01:00  P038871      14aede3f8ed INFO    LOGBCKUP state of service: indexserver, linux:31003, volume: 3, BackupLogStarted
      2015-01-15T15:01:20+01:00  P038871      14aede3f8ed INFO    LOGBCKUP state of service: indexserver, linux:31003, volume: 3, BackupLogSuccess

      >> 15 Minutes

      2015-01-15T15:15:07+01:00  P038871      14aedf1b48e INFO    LOGBCKUP state of service: indexserver, linux:31003, volume: 3, BackupLogStarted
      2015-01-15T15:16:20+01:00  P038871      14aedf1b48e INFO    LOGBCKUP state of service: indexserver, linux:31003, volume: 3, BackupLogSuccess

      >> 15 Minutes

      2015-01-15T15:30:07+01:00  P038871      14aedff702a INFO    LOGBCKUP state of service: indexserver, linux:31003, volume: 3, BackupLogStarted
      2015-01-15T15:31:20+01:00  P038871      14aedff702a INFO    LOGBCKUP state of service: indexserver, linux:31003, volume: 3, BackupLogSuccess

      Without grouping according to the service, it looks like a log backup happens every couple of minutes:

      2015-01-15T14:29:04+01:00  P038871      14aedc754db INFO    LOGBCKUP state of service: nameserver, linux:31001, volume: 1, BackupLogSuccess
      2015-01-15T14:31:20+01:00  P038871      14aedc881b0 INFO    LOGBCKUP state of service: indexserver, linux:31003, volume: 3, BackupLogSuccess
      2015-01-15T14:39:30+01:00  P038871      14aedd0e2c7 INFO    LOGBCKUP state of service: xsengine, linux:31007, volume: 2, BackupLogSuccess
      2015-01-15T14:44:04+01:00  P038871      14aedd5107c INFO    LOGBCKUP state of service: nameserver, linux:31001, volume: 1, BackupLogSuccess
      2015-01-15T14:46:20+01:00  P038871      14aedd63d50 INFO    LOGBCKUP state of service: indexserver, linux:31003, volume: 3, BackupLogSuccess
      2015-01-15T14:54:21+01:00  P038871      14aedde7c02 INFO    LOGBCKUP state of service: xsengine, linux:31007, volume: 2, BackupLogSuccess

      Best regards,

      Michael

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    Former Member
    Dec 22, 2014 at 03:38 PM

    Hi Olivier,

    Although the parameter below is defined on the HANA system

    log_backup_timeout_s=900

    The backups occur very frequently depending on the changes written in the log segment

    You will observe the following message in the BACKUP CONFIGURATION TAB when you point to *i* icon beside the BACKUP INTERVAL

    *The backup interval you specify is the longest amount of time that can pass before a new log backup. Log backups may be written more frequently if there is more Database activity*

    You must see log backups occurring at lower frequency when HANA is idle

    Most importantly each service has its own log backup so the parameter is allowing us to set the time out when Database is idle, when HANA is active it will write log backups more frequently and we may not control that

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    Former Member
    Dec 30, 2014 at 08:36 AM


    Log backup will happen for every 15 mins (log_backup_timeout_s=900) only if your HANA is idel. however, th frequency depends on the activity performed on the system

    Regards

    Pavan Gunda

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