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liverpool2507's avatar
liverpool2507
Level 4
11 years ago
Solved

High and low watermark

Hello Experts,

 

I need to check the basic watermark functionality with my NAS storage device using NBU. I have a filesystem to test (say 2 Gb). 

i have created a storage unit with CIFS UNC path and set the high watermark to 70% and low watermark to 30%.

I have also enabled temporary staging area and have given final detination as a diff storage unit. (not sure about staging part though)

i backed up 1Gb data and then again 1.5 gb of data. Howver, backup fails with the error "Disk storage unit is full(129)".

Can anyone explain why this error as when the value will reach to highest watermark , it should expire the images of the backup which has moved to final location.

Am i missing something obvious??

Any leads are welcomed.

Disk Type: Basic Disk

NBU: 7.6 

NBU Master: Windows 2008

 

Thanks in advance!!

Cheers!

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  • Marianne's avatar
    Marianne
    11 years ago

    Staging is duplication of the disk backup to other storage where more space exists for long-term retention. 
     

    The whole idea with Basic Disk is to keep backups there for a short period to enable quick restores.

    Because space is limited on normal disk, nobody can afford to just add more and more disk for long term retention.

    If you duplicate/stage to another Basic Disk Storage Unit, you will have the same proble - limited space.

    With tape you can simply add more media at a fraction of the cost of disk - local or NAS.

    So, if you backup to Basic Disk, you need to carefully look at how much you are backing up and decide how many FULL or INCR copies you would like to keep on the disk. The space (LUN) that you provision must be sufficient to hold this amount of data.

    Next is to provision suitable storage for long-term retention (e.g. 2 weeks for daily, 3 months for weekly, 12 months for monthly - whatever your company's recovery needs are). 
    You are going to battle to provide sufficient space on disk for long-term retention.

    With Disk staging, the backup retention is specified in the schedules of the Backup Policies.
    Backup to Disk is written with this retention.

    If you stage/duplicate these backups to the 'BIGGER' storage for long-term retention, the HWM can be applied.

    Any backups that are successfully duplicated to the secondary Storage Unit, can be expired and removed by NBU when the HWM is reached.

    If backups did not successfully duplicate to the STU specified in the Staging part of the Basic Disk config, the backups on disk cannot be expired and removed.

    Hope this helps!

     

    PS: 

    More info in  NetBackup Administrator's Guide, Volume I :

    Chapter 12 Staging backups

    This chapter includes the following topics:
    ■ About staging backups
    ■ About basic disk staging
    ■ Creating a basic disk staging storage unit
    ■ Configuring multiple copies in a relocation schedule
    ■ Disk staging storage unit size and capacity
    ■ Finding potential free space on a BasicDisk disk staging storage unit
    ■ Disk Staging Schedule dialog box
    ■ Initiating a relocation schedule manually

6 Replies

  • RamNagalla's avatar
    RamNagalla
    Moderator
    11 years ago

     it should expire the images of the backup which has moved to final location..

    yes , it do, but only with it reach the high watermark, it will start cleaning the Disk space by removing the images which has been moved to final destination.

    this is to make sure that the backup is avaliable in primary location longer time for quick recovery.

    are you sure that the first backup image is successfully duplicated to secondary location?

    did you verify that?

     

  • Marianne's avatar
    Marianne
    Level 6
    11 years ago

    I see the following in your post:

    (not sure about staging part though)

    Have you added a schedule in the STU during which staging (duplication to tape) will happen automatically?

    Can you see the duplication job in Activity Monitor on a regular basis?

    Only images successfully duplicated to tape can be removed when HWM is reached.
    You may want to change HWM back to 98%. Or at least above 90%. HWM of 70% on a relatively small LUN is way too low...

    Some reading matter:

    Disk Staging Relocation Behavior: http://www.symantec.com/docs/TECH44719

    Disk Staging Cleanup Behavior: http://www.symantec.com/docs/TECH66149 

  • liverpool2507's avatar
    liverpool2507
    Level 4
    11 years ago

    Hello RamNagalla,

    im not really sure about it as i have never used this functionality. I have enabled temporary staging area selected final destination stoarge unit as the other storage unit available. (not a tape libarary but a filesystem in NAS stoarge device)

    Does it specifically have to be a tape library??

    Can you please explain this??

     

  • liverpool2507's avatar
    liverpool2507
    Level 4
    11 years ago

    Hello Marianne,

    yes, i have added a schedule in STU and the final destination selcted is another Stoarge unit (NAS device).

    i also changed HWM to 92 % but the backup still fails and complains abt the disk storage being full.

    i have gone through the documents but really dint understand much how staging works. I understand the concept of watermark but staging is something that iam unable to understand. i mean  i dont understand what all selections do i need to make in the NBU GUI.

    If you could explain this in a layman term, it would be really great.

    Thanks!

     

     

  • Marianne's avatar
    Marianne
    Level 6
    11 years ago

    Staging is duplication of the disk backup to other storage where more space exists for long-term retention. 
     

    The whole idea with Basic Disk is to keep backups there for a short period to enable quick restores.

    Because space is limited on normal disk, nobody can afford to just add more and more disk for long term retention.

    If you duplicate/stage to another Basic Disk Storage Unit, you will have the same proble - limited space.

    With tape you can simply add more media at a fraction of the cost of disk - local or NAS.

    So, if you backup to Basic Disk, you need to carefully look at how much you are backing up and decide how many FULL or INCR copies you would like to keep on the disk. The space (LUN) that you provision must be sufficient to hold this amount of data.

    Next is to provision suitable storage for long-term retention (e.g. 2 weeks for daily, 3 months for weekly, 12 months for monthly - whatever your company's recovery needs are). 
    You are going to battle to provide sufficient space on disk for long-term retention.

    With Disk staging, the backup retention is specified in the schedules of the Backup Policies.
    Backup to Disk is written with this retention.

    If you stage/duplicate these backups to the 'BIGGER' storage for long-term retention, the HWM can be applied.

    Any backups that are successfully duplicated to the secondary Storage Unit, can be expired and removed by NBU when the HWM is reached.

    If backups did not successfully duplicate to the STU specified in the Staging part of the Basic Disk config, the backups on disk cannot be expired and removed.

    Hope this helps!

     

    PS: 

    More info in  NetBackup Administrator's Guide, Volume I :

    Chapter 12 Staging backups

    This chapter includes the following topics:
    ■ About staging backups
    ■ About basic disk staging
    ■ Creating a basic disk staging storage unit
    ■ Configuring multiple copies in a relocation schedule
    ■ Disk staging storage unit size and capacity
    ■ Finding potential free space on a BasicDisk disk staging storage unit
    ■ Disk Staging Schedule dialog box
    ■ Initiating a relocation schedule manually

  • liverpool2507's avatar
    liverpool2507
    Level 4
    11 years ago

    Thanks for the detailed explainition Marianne.

    I will go through the document and will post the result once i find out something related to the issue.

    Thanks!!