[Gluster-devel] Re: Feedback - Problem with the locks feature

Fri Feb 5 12:13:46 UTC 2010

Hi all,

Juste before I test this patch, I have an other bug to report
with/without the locks translator. As I said in my first email, I just
change from NFS to GlusterFS for my websites storage partition (about 15
000 websites).

I thought that only PHP sessions didnt "like" the posix locks but its
not. The other simple distributed partition for website files is
impacted :

With the posix locks, I have 30% of web server internal errors 500
(premature end of scripts headers), but without locks (I just change the
configuration), no 500 et no end of scripts headers. So I think there is
a link. (We have a huge trafic, maybe it could be another reason).

I'm applying the patch right know and will give you a feedback as soon
as possible.

Regards.

Le vendredi 05 février 2010 à 15:13 +0530, Pavan Vilas Sondur a écrit :
> Hi Samuel,
> Looking at log messages such as these:
> > > [2010-02-04 21:11:22] W [posix.c:246:posix_lstat_with_gen] posix1:
> > > Access to /data//.. (on dev 2049) is crossing device (64768)
> > > [2010-02-04 21:11:24] W [posix.c:246:posix_lstat_with_gen] posix1:
> > > Access to /data//.. (on dev 2049) is crossing device (64768)
> 
> It seems you are also running into bug 571 (http://bugs.gluster.com/cgi-bin/bugzilla3/show_bug.cgi?id=576). Can
> you apply this patch: http://patches.gluster.com/patch/2716 and let us know how it goes. Also, can you provide
> us details of the linux kernel version / Fuse Kernel Module versions on both the servers and the clients used
> apart from the output of the 'option trace on' in the locks translator.
> 
> Pavan
> 
> On 04/02/10 21:42 -0600, Anand Avati wrote:
> > 
> > ----- "Samuel Hassine" <samuel.hassine at gmail.com> wrote:
> > 
> > > Hi all,
> > > 
> > > For the PHP script with little write/read accesses I will try to find
> > > it (I dont remember exactly the syntax), but for PHP Sessions, the bug
> > > could be easily reproduced.
> > > 
> > > I just test it on a new very simple GlusterFS partition with no trafic
> > > (juste me), and I reproduced it immediatly.
> > > 
> > > Explainations:
> > > - 2 servers Debian Lenny stable
> > > - GlusterFS 3.0.0 in distributed mode (one server and multiple
> > > clients)
> > > - Lighttpd / PHP5 Fast-CGI
> > > 
> > > I juste mount the GlusterFS partition on the /var/www directory.
> > > 
> > > First of all, the PHP script you can execute:
> > > 
> > > <?php
> > > session_save_path('.');
> > > //if you want to verify if it worked
> > > //echo session_save_path();
> > > session_start();
> > > ?>
> > > 
> > > Secondly, there are 2 configurations if GlusterFS and, of course, one
> > > works and one does not.
> > > The client configuration is the same in the both cases:
> > > 
> > > glusterfs.vol
> > > volume test-1
> > > type protocol/client
> > > option transport-type tcp
> > > option remote-host test
> > > option transport.socket.nodelay on
> > > option transport.remote-port 6996
> > > option remote-subvolume brick1
> > > end-volume
> > > 
> > > volume writebehind
> > > type performance/write-behind
> > > option cache-size 4MB
> > > subvolumes test-1
> > > end-volume
> > > 
> > > volume readahead
> > > type performance/read-ahead
> > > option page-count 4
> > > subvolumes writebehind
> > > end-volume
> > > 
> > > volume iocache
> > > type performance/io-cache
> > > option cache-size 1GB
> > > option cache-timeout 1
> > > subvolumes readahead
> > > end-volume
> > > 
> > > volume quickread
> > > type performance/quick-read
> > > option cache-timeout 1
> > > option max-file-size 64kB
> > > subvolumes iocache
> > > end-volume
> > > 
> > > volume statprefetch
> > > type performance/stat-prefetch
> > > subvolumes quickread
> > > end-volume
> > > 
> > > Now the server configuration:
> > > 
> > > glusterfsd.vol (this doesnt work)
> > > volume posix1
> > > type storage/posix
> > > option directory /data
> > > end-volume
> > > 
> > > volume locks1
> > > type features/locks
> > > subvolumes posix1
> > > end-volume
> > > 
> > > volume brick1
> > > type performance/io-threads
> > > option thread-count 8
> > > subvolumes locks1
> > > end-volume
> > > 
> > > volume server-tcp
> > > type protocol/server
> > > option transport-type tcp
> > > option auth.addr.brick1.allow *
> > > option transport.socket.listen-port 6996
> > > option transport.socket.nodelay on
> > > subvolumes brick1
> > > end-volume
> > > 
> > > glusterfsd.vol (this works)
> > > volume posix1
> > > type storage/posix
> > > option directory /data
> > > end-volume
> > > 
> > > #volume locks1
> > > # type features/locks
> > > # subvolumes posix1
> > > #end-volume
> > > 
> > > volume brick1
> > > type performance/io-threads
> > > option thread-count 8
> > > subvolumes posix1
> > > end-volume
> > > 
> > > volume server-tcp
> > > type protocol/server
> > > option transport-type tcp
> > > option auth.addr.brick1.allow *
> > > option transport.socket.listen-port 6996
> > > option transport.socket.nodelay on
> > > subvolumes brick1
> > > end-volume
> > > 
> > > So, with the locks translator, you can execute the script one time (it
> > > will be ok) but the second time the session file is on the file system
> > > but locked and nobody can access to it. PHP freezes and processes
> > > coult not be killed.
> > > 
> > > When it's happened, I have nothing in client-side logs but I have 2
> > > kinds of message in the server-side logs:
> > > When I execute the script:
> > > [2010-02-04 21:11:22] W [posix.c:246:posix_lstat_with_gen] posix1:
> > > Access to /data//.. (on dev 2049) is crossing device (64768)
> > > [2010-02-04 21:11:24] W [posix.c:246:posix_lstat_with_gen] posix1:
> > > Access to /data//.. (on dev 2049) is crossing device (64768)
> > > 
> > > When I try to umount -f (disconnect the gluster):
> > > [2010-02-04 21:13:45] E [server-protocol.c:339:protocol_server_reply]
> > > protocol/server: frame 20: failed to submit. op= 26, type= 4
> > > 
> > > As I said I will try to find the other PHP script.
> > > 
> > > I hope this will help you.
> > 
> > I tried to reproduce the problem with your exact configuration (only changing 'option remote-host') from 1 server and 2 clients. I was not able to hit the problem with the configuration which is breaking for you. I used v3.0.0 as well.
> > 
> > Can you please turn 'option trace on' in the locks translator and give us the server log when the php session hangs?
> > 
> > Thanks,
> > Avati
> > 
> > 
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