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IO is frozen for snapshot / IO is thawed

  • November 23, 2004 at 3:09 pm

    #109339

    Following error message on SQL Server log.

    (SQL Server 2000 SP3a on Windows 2003 ADV server 8 GB RAM)

    Backups are not running at this time.  Transaction backup runs every 2 hours but very low transactions (Activity on the server)

    I have found following error messages in SQL Server Agent log files. How can I resolve it?

    2004-11-22 05:13:04.71 spid89 Database USERDB3: IO is frozen for snapshot

    2004-11-22 05:13:04.71 spid88 Database USERDB2: IO is frozen for snapshot

    2004-11-22 05:13:04.71 spid92 Database model: IO is frozen for snapshot

    2004-11-22 05:13:04.71 spid93 Database msdb: IO is frozen for snapshot

    2004-11-22 05:13:04.71 spid94 Database USERDB1: IO is frozen for snapshot

    2004-11-22 05:13:04.93 spid90 Database master: IO is frozen for snapshot

    2004-11-22 05:13:06.51 spid88 Database USERDB2: IO is thawed

    2004-11-22 05:13:06.51 spid89 Database USERDB3: IO is thawed

    2004-11-22 05:13:06.51 spid93 Database msdb: IO is thawed

    2004-11-22 05:13:06.51 spid92 Database model: IO is thawed

    2004-11-22 05:13:06.51 spid94 Database USERDB1: IO is thawed

    2004-11-22 05:13:06.51 spid90 Database master: IO is thawed

    Thanks for your help in advance.

     

  • November 24, 2004 at 10:04 am

    #531438

    We get that also when we EMC frame tools to create an SRDF to copy to our disaster site. Do you have an EMC frame for your data disk(s).


    Pat Mong

  • November 24, 2004 at 10:07 am

    #531439

    Unfortunately, We do not have EMC frame tools. Only one third party component that we run is veritas backup utility for tape back up every night.

  • November 24, 2004 at 10:58 am

    #531446

    So your server uses internal disk? Does this happen every day? At the same timeframe? Are there any SQL jobs or scheduled tasks running then?

     


    Pat Mong

  • November 24, 2004 at 10:59 am

    #531448

    Also, you have almost a 2 minute stoppage of I/O. That's a LONG time.


    Pat Mong

  • November 24, 2004 at 2:57 pm

    #531476

    It's usually between 5 and 6 AM. SQL Server backup jobs run between 8:00 pm to 9:00 pm. It takes less than 3 minutes for each backup to complete. Backups are on disk and nightly veritas pickups backup files and backups on tape.

  • November 25, 2004 at 5:49 pm

    #531565

    These aren't error messages.  They are messages generated by whatever third party backup tool you are using at a file level.  I'm guessing you have a third party tool with a SQL Agent that allows it to backup your databases directly.

    We get the exact same messages from our SAN while the snapshot backups take place.  I still have nativel SQL backups running though.  While your databases are 'frozen' they are essentially offline and no users will be able to connect.

    In your case I think your Veritas backup is actually taking a snapshot backup of your databases, rather than only backing up your SQL backup files.

  • November 29, 2004 at 12:12 pm

    #531768

    Thanks for your responses. We do run Veritas backup component. I will check the schedule and view history to find out what time it hits the server in question for tape backup?

    Thanks

  • March 3, 2005 at 6:14 am

    #545182

    I had the same problem on our W2K3 machine. Finally I figured out what caused the problem: ntbackup. This program has a commandline switch called /SNAP. Whenever you run a ntbackup, even to backup 2 simple text files, all open files are frozen for a moment. Somehow, if your machine contains a SQL Server instance, a dump for all databases is created to a virtual device.

    Don't ask me why

     

    Martin Rutten,

    Wildher ICT Solutions

  • November 2, 2006 at 8:24 am

    #669499

    Thanks. Your contributions were helpful.

    J

  • December 20, 2006 at 12:06 am

    #679054

    I am also getting this error messages. I am confussed is that NTBackup or SAN causing this problem

     

    Sivaprasad S - [ SIVA ][/url]http://sivasql.blogspot.com/[/url]

  • July 31, 2008 at 1:06 am

    #851019

    It seems like NTBACKUP tries to take a snapshot of the drive eventhough only one folder in that drives is selected for backup. This snapshot freezes the databases if their files are on the above drive.

    Does anybody know if there is any solution for this other than the command line switch?

  • September 24, 2009 at 5:34 am

    #1057941

    I haven't tried this Hotfix yet. But it suggested this hotfix may fix the issue that ntbackup has. Below link for your reference.

    http://support.microsoft.com/kb/903643

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