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Issue with disk space Recovery Window

serandrzej
serandrzej Member Posts: 33 Blue Ribbon
edited Jun 19, 2020 5:54PM in Recovery Manager (RMAN)

Hello,

Oracle 12.2 APR2020Patch

I have question about disk space management with RMAN.

I had retention policy of 3 days and after disk expansion I expanded it to 7 days.

Recently backup failed and I see Archivelogs consumed ca 320G. I reduced Recovery Window back to 3 days and I could complete backup.

1 day of archive logs consumes ca 80G.

Now Archivelogs consume 250 G and backup 177G.

Is it wise to have recovery window or maybe it would be better to replace it with number of copies eg. 2 ? And hint how I can improve this situation ?

Answers

  • EdStevens
    EdStevens Member Posts: 28,529 Gold Crown
    edited Jun 19, 2020 5:41PM
    serandrzej wrote:Hello,Oracle 12.2 APR2020PatchI have question about disk space management with RMAN.I had retention policy of 3 days and after disk expansion I expanded it to 7 days.Recently backup failed and I see Archivelogs consumed ca 320G. I reduced Recovery Window back to 3 days and I could complete backup.1 day of archive logs consumes ca 80G.Now Archivelogs consume 250 G and backup 177G.Is it wise to have recovery window or maybe it would be better to replace it with number of copies eg. 2 ? And hint how I can improve this situation ?

    I much prefer recovery window.

    What housekeeping are you doing on your backups and archivelogs?

    Ultimately, you are going to have to have enough disk space to hold what you need to guarantee recovery .....  you can't haul 5 tons of freight in a half-ton pickup truck.

  • Dude!
    Dude! Member Posts: 22,826 Black Diamond
    edited Jun 19, 2020 5:54PM

    To delete any backups that are older than your RMAN retention policy is not what a retention policy does or was mean to do. The RMAN retention policy defines what RMAN backups of datafiles and archivelogs are not to be considered obsolete, or in other words, are required to fulfill restore and recovery to accomplish the retention period. For example, if you last incremental level 0 backup was 1 month ago, no backup since then can be obsolete, regardless of your retention setting.

    RMAN does not delete any files unless you instruct it to do. So normally, you would evaluate which backups are currently obsolete running RMAN report obsolete, followed by RMAN delete obsolete. If you want automatic storage management, than this not done by RMAN, but Oracle database and using FRA (fast recovery area). The later will automatically purge obsolete backup and recovery data when there is free space pressure.

    Also, what people often seem to overlook, is that your control_file_record_keep_time parameter must be larger than your retention period, unless you check for obsolete backups every week. The documentation about this parameter will give you more info.