[Linux-cluster] hung when 3rd nodes mounting the gfs using dlm

[Leonardo Rodrigues de Mello]

What command had you used to create the gfs filesystem ? 

GFS need one journal for each server that mount the filesystem. If you have created the filesystem only with 2 journals, you won't be able to use more than two machines. 

The is used among other things to restore the filesystem in case of server failure. 

If gfs in the current architeture permits you to mount in more servers than the number of journals you have, will damage the filesystem, maybe this is one of the reasons for gfs block access from more servers than the number of journals.

01 - To specify the number of journals at filesystem creation: 

with the option -j number at mkfs.gfs where number is the number of machines. 

for 4 machines the option will be: -j 4 


02 - To increase the number of journals in filesystem that has been already created: (possibly that is your case)

for this task exist the tool gfs_jadd. see it manpage
to use this tool, you need to mount the gfs filesystem in the machine that will increase the number of journal. 

gfs_jadd -j number_to_increase /gfs/filesystem/mount/point

number_to_increase must be how many journals you want to add to that filesystem, by default this number is 1. in your case with four servers: (you already have 2 journals, could be like: 

gfs_jadd -j 2 /gfs/filesystem/mount/point

some times gfs_jadd doesnt work, because there isnt space in the disk for the journal creation. in that case the best solution i know is to format the filesystem specifying the correct number of journals.


Best Regards
Leonardo Rodrigues de Mello


-----Original Message-----
From:	linux-cluster-bounces at redhat.com on behalf of Kent Chen
Sent:	ter 1/8/2006 10:23
To:	linux-cluster at redhat.com
Cc:	
Subject:	[Linux-cluster] hung when 3rd nodes mounting the gfs using dlm

I connect 4 SUN x4100 (2 AMD dual core, 2G RAM ) to a SUN Storage 3510 with
a silkworm 200e FC switch.
the OS is RHEL 4 U3 for X86_64.

I make 2 GFS FS,one called Alpha:gfs1, another called Alpha:gfs2

All things seems good when only 2 nodes mount GFS.

Once 3rd node mount the GFS, the command hang.

Is there anyone who encounted the similar problem?

Is it a bug of GFS?



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