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  • 1.  Problems with ONTAPE

    Posted 04/03/23 07:07 PM

    Dear colleagues:

    I am backing up the database (Informix 7.31 TD6) to tape and disk.

    Until last week there had been no issues, except that the tapes occasionally slowed down.

    Today I have found that both the tapes and the copies on disk are very slow. In addition, ONTAPE reached 50% and stopped there, without throwing any error or warning messages.

    Example: The tapes took approximately 15 minutes to copy everything. And the discs took longer, up to 50 minutes, but not more than that.

    For three months I have been copying on the same tapes and discs. I have 10 tapes, and I make one backup in the morning and one in the evening, so each tape is identified as 01-Monday-Morning, 02-Monday-Night, and so on until Friday.
    In the case of disk backup, I have two disks, and in one I make the copy at noon and in the other at night.
    Could it have happened that the discs have deteriorated and filled the tapes?

    Thank you in advance for your attention.

    Greetings!

    Gustavo



    ------------------------------
    Gustavo Echenique
    ------------------------------


  • 2.  RE: Problems with ONTAPE

    Posted 04/04/23 09:05 AM

    Gustavo:

    It is not clear whether the issue is that ontape is slow or that copying the archive files around is slow?

    One thing, the occasional slow archives are mainly because you are using an truly ancient release of Informix. There was a bug of sorts in the archive process which was fixed in a later release of 7.31 (no longer available) that caused archives to take MUCH longer than usual if the "timestamp" on pages on disk had wrapped past 2^31 causing ontape to stop what it was doing to update the timestamp on all "older" pages with high timestamp values (necessary to make level 2 and level 3 archives to work properly). That algorithm was later changed so that no longer happens. But I'm not sure that is what you are referring to in this post.

    It goes without saying that you should probably upgrade to a supported version of Informix. The current release is v14.10.FC10 which is probably 2X+ faster with tons of features. 

    Art



    ------------------------------
    Art S. Kagel, President and Principal Consultant
    ASK Database Management Corp.
    www.askdbmgt.com
    ------------------------------



  • 3.  RE: Problems with ONTAPE

    Posted 04/05/23 06:48 PM

    Hello Art!

    I'm sorry I wasn't more clear in my explanation.

    Until last Friday I had been making backup copies with ONTAPE on tapes and disks.

    The speed of the tapes was good, they completed a backup of almost 300 GB in 20 minutes, and the disks in 50 minutes.

    I was very happy with that, but since Monday, ONTAPE reaches 50% and it takes a long, long time until it continues to advance. In the case of discs, it remains at that percentage for at least 3 and a half hours.



    ------------------------------
    Gustavo Echenique
    ------------------------------

    Original Message


  • 4.  RE: Problems with ONTAPE

    Posted 04/06/23 12:50 AM

    Gustavo,

    Are you absolutely certain nothing else in the environment changed?
    Usually when something like this happens, something changed somewhere;
    the trick is finding what and where.

    Some thoughts:
    * Are some other processes/tasks running on the same server at the time
      the backups run?  Are more users on at the time the backup runs?  Some
      one kick off a long running query?

    You didn't mention what OS you are on.  If Unix/Linux, can you run top(1)
    at the time the backups grind to a crawl to see what is going on?
    On Windows, use task manager and sort by CPU, memory, or disk to see if
    something else is competing for system resources.

    * Are the tapes old?  Tapes tend to wear our faster than disks.
      Maybe errors writing to a bad tape?  Or a hardware issue with a tape
      or disk drive?  Check syslog on Unix or Windows event log for hardware
      errors at the time the backups run.

    * Has the size or structure of the data changed significantly?

    Also your original message said 15 minutes to write to tape but 50 minutes
    for the discs.  Are you burning to CD/DVD media?  If you are copying to
    another hard drive, the drives should be faster than writing to tape.
    Writing to CD/DVD media I would expect they would take longer.

    Are you able to write the backups directly to hard disk either on the
    local system, say in another directory, or over the network via NFS or a
    Samba share?  See if the backups are still slow.

    scot


    Original Message


  • 5.  RE: Problems with ONTAPE

    Posted 04/07/23 09:29 AM

    I think Art is referring to the very old bug B101062 ARCHIVE PERFORMANCE DEGRADATION WHEN MANY CALLS TO ARC_VERY_OLD_PAGE()

    You can refer to the URL below and follow the analysis steps to confirm whether you are running into the same issue. 

    https://www.ibm.com/support/pages/informix-ontape-backup-runs-slow

    Anyway 7.31.TD6 is too ancient, best to consider migrating to the latest version of Informix 14.10.



    ------------------------------
    Casey Tan
    ------------------------------

    Original Message


  • 6.  RE: Problems with ONTAPE

    Posted 04/09/23 12:31 AM

    I stands by my analysis!

    Art



    ------------------------------
    Art S. Kagel, President and Principal Consultant
    ASK Database Management Corp.
    www.askdbmgt.com
    ------------------------------

    Original Message


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