Re: [Gluster-users] rogue file

2013-07-09 Thread Eco Willson
1. What is gluster supposed to do when a non-gluster file (no gluster xattrs) 
appears on a gluster brick?
If the file is not accessed via the client mount point, nothing will happen to 
the file from a Gluster standpoint

2. What does the current implementation actually do?
Once the file is accessed from the client mount point, the xattrs are appended 
to the file

3. Does it matter whether it is or is not a replicated brick?
4. Does it matter whether it is a striped brick?
Neither of these should matter.

Thinking about these scenarios after the file has been written:

A. No one ever looks at the file
Nothing will happen in this case

B. A self-heal runs
If the file has not had xattrs appended to it, self-heal will skip the file

C. A directory read gets done on that sub-directory
ls by itself will not append the xattrs, but a `stat` of the file will

D. Someone actually tries to read the file (like if it was called readme.txt 
or some other common name)
A stat or vi in this case will append the xattrs.

In 3.4beta4 it appears even an ls on the file will work.


Thanks,

Eco

- Original Message -
From: Ted Miller tmil...@hcjb.org
To: Gluster-users@gluster.org
Sent: Monday, July 8, 2013 3:20:17 PM
Subject: [Gluster-users] rogue file

A multi-part question relating to a scenario where a rogue program/person 
writes a file into a brick through the underlying file system (e.g. XFS) 
without going through glusterfs?

1. What is gluster supposed to do when a non-gluster file (no gluster xattrs) 
appears on a gluster brick?

2. What does the current implementation actually do?

3. Does it matter whether it is or is not a replicated brick?

4. Does it matter whether it is a striped brick?


Thinking about these scenarios after the file has been written:

A. No one ever looks at the file
B. A self-heal runs
C. A directory read gets done on that sub-directory
D. Someone actually tries to read the file (like if it was called readme.txt 
or some other common name)

Don't have an example at hand, just wondering what would happen as I work on 
putting together a test bed that will be either replica 2 or replica 4, 
unstriped.

Ted Miller
Elkhart, IN, USA


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Re: [Gluster-users] rogue file

2013-07-09 Thread Jeff Darcy

On 07/09/2013 02:01 PM, Eco Willson wrote:

Thinking about these scenarios after the file has been written:

A. No one ever looks at the file
Nothing will happen in this case

B. A self-heal runs
If the file has not had xattrs appended to it, self-heal will skip the file

C. A directory read gets done on that sub-directory
ls by itself will not append the xattrs, but a `stat` of the file will

D. Someone actually tries to read the file (like if it was called readme.txt
or some other common name)
A stat or vi in this case will append the xattrs.

In 3.4beta4 it appears even an ls on the file will work.


That seems accurate in the case where the rogue file is the only one with 
that path.  However, if another brick within the same replica set has a file 
with that path, something different will happen.  Specifically, the rogue 
file will be observed to have no GFID, which will cause operations to fail 
because of a GFID mismatch.  Technically that's not split brain, but the 
practical implications are the same.



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[Gluster-users] rogue file

2013-07-08 Thread Ted Miller
A multi-part question relating to a scenario where a rogue program/person 
writes a file into a brick through the underlying file system (e.g. XFS) 
without going through glusterfs?


1. What is gluster supposed to do when a non-gluster file (no gluster xattrs) 
appears on a gluster brick?


2. What does the current implementation actually do?

3. Does it matter whether it is or is not a replicated brick?

4. Does it matter whether it is a striped brick?


Thinking about these scenarios after the file has been written:

A. No one ever looks at the file
B. A self-heal runs
C. A directory read gets done on that sub-directory
D. Someone actually tries to read the file (like if it was called readme.txt 
or some other common name)


Don't have an example at hand, just wondering what would happen as I work on 
putting together a test bed that will be either replica 2 or replica 4, 
unstriped.


Ted Miller
Elkhart, IN, USA


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