Re: [Gluster-devel] error while reading from an open file

[Brian Hirt]

Vijay,

Yes, I am using the same distributed-replicate scenario.

The file in the export directory does contains the correct  
information, but somewhere along the line something being communicated  
to the operating system by gluster must be wrong.  I say this because  
the client trying to read from an open file is not getting the proper  
data returned from the system calls which seems to point to a bug in  
glusterfs.

I've also run into something the might be related but seems much more  
serious.  A program writing to a glusterfs file will fail when you  
restart You can recreate the problem by:

	1) have a program open a file on a glusterfs, write data to a file  
periodically
	2) while the file is being written to, one by one restart all the  
gluster servers, waiting for the previous server to come back online

At all points in time, three of the four gluster servers are up and  
running, however the program trying to write data to the file fails.   
This is a huge issue for any program that keeps a file open for  
writing for more than a second or two.

As for the temporary files created by rsync, I'm willing to believe  
they are benign in this particular situation.  However, something  
seems wrong the idea that gluster would expect to have a file, try to  
lstat it only to find it's not there.   Shouldn't gluster know where  
the files it maintains are?  It really feels like a race condition  
that will be triggered in other situations where it's not so benign.

Thanks for any help you can provide.

--brian

On Aug 30, 2009, at 10:05 AM, Vijay Bellur wrote:

> Brian Hirt wrote:
> > I'm running into some problems where one process is writing a log  
> > file to a and another is reading from it.  The process reading the  
> > file is not behaving as expected.
> I am assuming you are using the distributed-replicate scenario that  
> you mentioned in the previous mail. Can you please confirm if the  
> file in the export
> directory contains data that  you did not intend to create?
>
> > I'm also continuing to get hundreds of the errors I mentioned in  
> > that message with rsync.
> >
> > [2009-08-28 10:21:20] E [posix.c:1155:posix_chmod] posix: lstat on / 
> > gluster/exports/redacted/.1218486082-01.jpg.nkOkw9 failed: No such  
> > file or directory
>
> These are usually to do with temporary files created during a rsync.  
> These error messages would be benign in nature unless you notice a  
> discrepancy between the original and rsync'd directories.
>
> Regards,
> Vijay