[Gluster-users] file open/write/move causing blank content in files

[Daryn Hanright]

Hi

So noone else has seen this issue or can replicate it?

Perhaps waiting for Gluster 3.4 might help?

Am not sure what I can do to solve the issues I'm seeing.

cheers
Daryn


On Thu, Jun 13, 2013 at 2:26 PM, Daryn Hanright <daz at planetnz.com> wrote:

> Hi!
>
> Just a follow up to this issue. I also noticed if I try to touch the blank
> file, sometimes I get a PHP warning
>
> PHP Warning:  touch(): Utime failed: Permission denied etc etc
>
> So I can't even guarantee that touching a file brings its contents back.
>
> Any ideas on what might be happening?
>
> Its quite confusing, because most of the time, everything looks great.
> Files get replicated & it just works.
>
> cheers
> Daryn
>
>
> On Wed, Jun 12, 2013 at 2:24 PM, Daryn Hanright <daz at planetnz.com> wrote:
>
>> Hi
>>
>> Have found an issue with our installation of gluster, and need some
>> advice on how to procede.
>>
>> I wrote out a bug report detailing the issue.
>>
>> https://bugzilla.redhat.com/show_bug.cgi?id=971630
>>
>>
>> I'm not sure if its a gluster configuration problem, or an actual bug. Or
>> even a VM thing. Or combination of both.
>>
>> Will briefly describe the issue I am seeing (bug report above more
>> detailed).
>>
>> In an application I'm developing on a 2 brick gluster installation (2
>> Centos 6 VM's), occasionally I'd see a file that appeared to exist in both.
>>
>> The permissions on both files exactly the same. Also the timestamp. I
>> would however notice in the application logs a few "permission denied"
>> errors occuring, I'm assuming because my application is trying to read a
>> file thats currently being written.
>>
>> This is the strange bit. When I cat/less the file, on 1 server its blank.
>> On the other the content of the file is fine. If I 'touch' the blank file
>> the content of the file comes back.
>>
>> So I wrote a couple of quick & dirty PHP scripts effectively duplicating
>> what the application tries todo.
>>
>> write.php - this basically opens and write a file to a directory (in a
>> loop - 100 files). I read its contents in. I then move the file to another
>> gluster directory.
>> read.php -  finds files in both directories & tries to read contents in.
>> In a loop with no time delay in reading
>>
>> Every single time, I end up with at least 1 file (mostly more than 1)
>> which has the characteristics I've described in both the original
>> directory, and the directory where the file was moved. Indicating that
>> either a file->open->write or a file->mv AND reading the files at the same
>> time causes it.
>>
>> It would be nice if I could figure out what might be happening here. Is
>> it a bug? Maybe a config issue?
>>
>> # gluster volume info
>>
>> Volume Name: prxvol
>> Type: Replicate
>> Volume ID: b5879503-3c6b-4556-b6ee-e600208150a7
>> Status: Started
>> Number of Bricks: 1 x 2 = 2
>> Transport-type: tcp
>> Bricks:
>> Brick1: 10.178.19.254:/data
>> Brick2: 10.177.17.23:/data
>> Options Reconfigured:
>> auth.allow: 10.178.19.254,10.177.17.23
>> diagnostics.brick-log-level: INFO
>> diagnostics.client-log-level: INFO
>> cluster.data-self-heal-algorithm: diff
>>
>>
>>
>> cheers
>> Daryn
>>
>
>
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