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  1. #1
    Join Date
    Jun 2004
    Posts
    1

    Unanswered: Ingres II + Netapp + snapshots

    Hello,

    Has anyone had some expreriences with this combination?

    The question: what possibilities does Ingres have to lock / freeze database-activity for a few seconds (and sync data to disk) in order to make a Snapshot? E.g. has the database to be in a "down" state before making a consistent snapshot?

    Kind regards,

    Koert Gielen

  2. #2
    Join Date
    Jul 2003
    Location
    England
    Posts
    152
    Quote Originally Posted by Koert Gielen
    Hello,

    Has anyone had some expreriences with this combination?

    The question: what possibilities does Ingres have to lock / freeze database-activity for a few seconds (and sync data to disk) in order to make a Snapshot? E.g. has the database to be in a "down" state before making a consistent snapshot?

    Kind regards,

    Koert Gielen
    Koert

    Short answer is yes - the db has to be down to get a consistent snapshot - I assume that you are breaking some disk mirror to take this snapshot. If that is what you are doing then you will have to shut the db down to write all the memory to disk. (We used to take our nightly backup/report db refresh in this fashion at a company I used to work for)

    If you simply want a backup of the db, then an online checkpoint is the way to do it (if you have enough time in your batch)
    Regards
    Dbabren

  3. #3
    Join Date
    Nov 2002
    Posts
    33
    Koert,

    Probably the easiest way to ensure consistency would be to shut down ingres. However all you really need is to force a consistency point (all committed transactions flushed to disk) and exclusively lock the database while you're taking the snapshot. This is exactly what an offline checkpoint does. However what you don't want to do is actually back up the database files as the snapshot is doing that for you. So one way to achieve this would be to create a customized checkpoint template file which either does nothing or actually calls the snapshot.

    I'm not familiar enough with Netapps to know but it's possible that you can only run the commands as root? In which case you have a little bit of a scripting challenge - but it should still be doable. Alternately you could make root a security administrator in Ingres (it's already a user by default) and get root to do the checkpoint.

    You might also want to look at this http://supportconnectw.ca.com/premiu...odocs/4323.pdf (need a supportconnect login) - which describes this kind of approach applied to HP LVM disk mirroring. The concept is the same the details are different.

    HTH
    Paul
    Paul Mason

  4. #4
    Join Date
    Nov 2002
    Posts
    33
    Quote Originally Posted by PaulMason
    Alternately you could make root a security administrator in Ingres (it's already a user by default) and get root to do the checkpoint.
    I wasn't thinking straight when I wrote that. Even running the checkpoint as root the commands are run as Ingres because of the setuid on ckpdb. However it might make the scripting of the job a little easier.
    Paul Mason

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