Forum Discussion

NHL's avatar
NHL
Level 4
14 years ago

backup retention with incrementals

Hi

we need to move from full backups to incrementals due to increased backup load.

However I can't find any info in the docs about how often netbackup creates a level 0 backup. We are going to have a schedule with a retention of 2 weeks, does that mean netbackup will only perform a full level 0 backukp once every 2 weeks?

Thanks

Nick .

7.1.x and Earlier
Backing Up
Backup and Recovery
NetBackup
  • Marianne's avatar
    Marianne
    14 years ago

    Please read through the "Schedule" section of the NetBackup AdminGuide I. It explains in detail how frequency and retention levels can be planned.

    Here is an extract from NBU 7 Administrator's Guide for Windows, I  http://www.symantec.com/docs/TECH127079  (please read the entire section for more clarity):

    Precautions for assigning retention periods
    For full backups, specify a time period that is longer than the frequency setting
    for the schedule. (The frequency is how often the backup runs). For example, if
    the frequency for a full backup is one week, specify a retention period of two to
    four weeks. Two to four weeks provides enough of a margin to ensure that the
    current full backup does not expire before the next full backup occurs.
    For cumulative incremental backups, specify a time period that is longer than the
    frequency setting for the schedule. For example, if the frequency setting is one
    day, specify a retention period of one week. One week provides enough of a margin
    to ensure that the current cumulative-incremental backup does not expire before
    the next successful one occurs. A complete restore requires the previous full
    backup plus the most recent cumulative-incremental backup.
    For differential incremental backups, specify a time period that is longer than the
    period between full backups. For example, if full backups occur weekly, save the
    incremental backups for two weeks.
    A complete restore requires the previous full backup plus all subsequent
    incremental backups.
    ■ NetBackup does not track backups after the retention period expires. Assign
    an adequate retention period as recovering files after the retention period
    expires is difficult or impossible.
    ■ Within a policy, assign a longer retention period to full backups than to
    incremental backups. It may not be possible to restore all the files if the full
    backup expires before the incremental backups.

     

    PLEASE note the reference to 'Within a policy' - full and incremental schedules must be in the SAME policy.

  • Paramesh's avatar
    Paramesh
    Level 4
    14 years ago

    hi,,

     

    if u create a backup policy with 2weeks(level 0) retention then netbackup will keep that image for 2weeks and it doesnot matter whether ur backup frequency is one day or 1 week.....

     

    retention is different and backup frequency is different here...

  • Andy_Welburn's avatar
    Andy_Welburn
    Level 6
    14 years ago

    - depends on how often you schedule it!

    Just ensure your retention on your FULLS is greater than that of your incrementals - after all the incrementals are based on the fulls & if the latter expire first then you will have issues if you need to do a full restore in a DR situation.

    We schedule FULLS once a month retained for a year & differential incrementals daily thereafter interspersed with weekly cumulative incrementals - the incrementals being retained for one month.

  • rizwan84tx's avatar
    rizwan84tx
    Level 6
    14 years ago

    Consider that, if you schedule a full backup to run on month end with 1 Year retention. Netbackup will run one Full backup per month and the data is protected for a year only for that particular full backup.

  • Marianne's avatar
    Marianne
    Level 6
    14 years ago

    Please read through the "Schedule" section of the NetBackup AdminGuide I. It explains in detail how frequency and retention levels can be planned.

    Here is an extract from NBU 7 Administrator's Guide for Windows, I  http://www.symantec.com/docs/TECH127079  (please read the entire section for more clarity):

    Precautions for assigning retention periods
    For full backups, specify a time period that is longer than the frequency setting
    for the schedule. (The frequency is how often the backup runs). For example, if
    the frequency for a full backup is one week, specify a retention period of two to
    four weeks. Two to four weeks provides enough of a margin to ensure that the
    current full backup does not expire before the next full backup occurs.
    For cumulative incremental backups, specify a time period that is longer than the
    frequency setting for the schedule. For example, if the frequency setting is one
    day, specify a retention period of one week. One week provides enough of a margin
    to ensure that the current cumulative-incremental backup does not expire before
    the next successful one occurs. A complete restore requires the previous full
    backup plus the most recent cumulative-incremental backup.
    For differential incremental backups, specify a time period that is longer than the
    period between full backups. For example, if full backups occur weekly, save the
    incremental backups for two weeks.
    A complete restore requires the previous full backup plus all subsequent
    incremental backups.
    ■ NetBackup does not track backups after the retention period expires. Assign
    an adequate retention period as recovering files after the retention period
    expires is difficult or impossible.
    ■ Within a policy, assign a longer retention period to full backups than to
    incremental backups. It may not be possible to restore all the files if the full
    backup expires before the incremental backups.

     

    PLEASE note the reference to 'Within a policy' - full and incremental schedules must be in the SAME policy.

  • NHL's avatar
    NHL
    Level 4
    14 years ago

    Thanks all for your comments, appreciated.

    I have a differential incremental schedule that runs mon-thurs. And a schedule in a different policy that runs a full complete backup every Friday. However the full Friday backup also backs up more data than the incremental.

    I guess I need to read the doc mentioned above, I'll do that and get back to you folk if I have any more quiestions.

    Thanks again.

  • Andy_Welburn's avatar
    Andy_Welburn
    Level 6
    14 years ago

    full"

    Don't forget what Marianne stated - for the incrementals to run as such they must be in the same policy as the (or at least a) full

  • NHL's avatar
    NHL
    Level 4
    14 years ago

    That means the full and the incrementals will have to go to the same tape volumt pool doesn't it? I ask because we currently have different tape pools for the daily(incremental) and weekly(full) backups.