Re: Open Files

jcduell_at_lbl_dot_gov
Date: Tue Sep 06 2005 - 11:06:38 PDT

  • Next message: Paul H. Hargrove: "Re: Open Files"
    On Tue, Sep 06, 2005 at 01:35:16PM +0300, Emmanuel Grumbach wrote:
    > Hello,
    > 
    > I have read the pages on Checkpoint. It seems very interesting but there
    > is an info I could not get. Does BLCR support open files ? In other words,
    > if my application has opened a file for reading/writing (writing with lock
    > seems more fun) and I checkpoint it, supposing the file still exists
    > (logically (path) or on the same inodes), will BLCR be able to open it
    > again ?
    
    Yes, we handle the general case of an application with open files.  If
    the file exists with the same *logical* pathname (the inode number does
    not need to be the same), the file will be reopened, and seeked to the
    same position as it was at checkpoint time.  This means that if you have
    a global filesystem, you will be able to restart a program on a
    different node in a cluster, so long as all the files the program needs
    to restart (including shared libraries and the executable's program
    text, etc.) are in the same logical place in the file system.
    
    Note that we do not handle certain types of files (TCP or Unix domain
    sockets, for instance).
    
    -- 
    Jason Duell             Future Technologies Group
    <jcduell_at_lbl_dot_gov>       Computational Research Division
    Tel: +1-510-495-2354    Lawrence Berkeley National Laboratory
    

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