Dual primary mounted partitions not showing changes

[dascione]

I've been working at creating a highly available set of host servers for a linux diskless boot cluster.  Each host machine is fitted with redundant power supplies and two 1TB drives in a Raid-1 configuration.

When I first started this project they each had twin 160GB drives.  In my original setup I had both nodes acting as primary systems so that I could mount /dev/drbd0 to my /data directory and see changes immediately.  It had worked in the past where I could make a file in /data on the first machine and it would show up in the /data directory on the second machine.  One day this had stopped working where if I made a file on the first machine it would display on the second one until I unmounted /data and remounted it to the /dev/drbd0 disk.  This is when I bought the new disks and decided to start from scratch.

Below is my configuration file, sda8 is an 820GB partition which is used for all of the data I want to replicate, currently populated with ~10GB of data.  Sda7 is my metadisk partition which is 500MB large clearly more than needed by drbd.

Also you will notice "incon-degr-cmd "halt -f";" is commented out.  This is because when I go to actually use it drbd throws an error when reloading the configuration and I'm not sure why that is either.

resource r0 {
  protocol C;
  #incon-degr-cmd "halt -f";
  net {
    allow-two-primaries;
    after-sb-0pri discard-zero-changes;
    after-sb-1pri discard-secondary;
    after-sb-2pri disconnect;
  }
  startup {
    become-primary-on both;
  }
  disk {
    on-io-error detach;
  }
  syncer {
    rate 128M; # Note: 'M' is MegaBytes, not MegaBits
  }
  on dh1.domain.com {
    device    /dev/drbd0;
    disk      /dev/sda8;
    address   192.168.1.140:7789;
    meta-disk  /dev/sda7[0];
  }
  on dh2.domain.com {
    device    /dev/drbd0;
    disk      /dev/sda8;
    address   192.168.1.141:7789;
    meta-disk  /dev/sda7[0];
  }
}

[Iustin Pop-2]

On Wed, Nov 04, 2009 at 05:27:28AM -0800, dascione wrote:
> When I first started this project they each had twin 160GB drives.  In my
> original setup I had both nodes acting as primary systems so that I could
> mount /dev/drbd0 to my /data directory and see changes immediately.  It had
> worked in the past where I could make a file in /data on the first machine
> and it would show up in the /data directory on the second machine.  One day
> this had stopped working where if I made a file on the first machine it
> would display on the second one until I unmounted /data and remounted it to
> the /dev/drbd0 disk.

What filesystem are you using?

regards,
iustin
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[Madison Kelly]

Iustin Pop wrote:

> On Wed, Nov 04, 2009 at 05:27:28AM -0800, dascione wrote:
>> When I first started this project they each had twin 160GB drives.  In my
>> original setup I had both nodes acting as primary systems so that I could
>> mount /dev/drbd0 to my /data directory and see changes immediately.  It had
>> worked in the past where I could make a file in /data on the first machine
>> and it would show up in the /data directory on the second machine.  One day
>> this had stopped working where if I made a file on the first machine it
>> would display on the second one until I unmounted /data and remounted it to
>> the /dev/drbd0 disk.
>
> What filesystem are you using?
>
> regards,
> iustin

Also, what does 'cat /proc/drbd' show on either node?

I think iustin is asking for a similar reason that I was going to ask;
Is the filesystem cluster-aware and properly implementing locking?

Madi
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[dascione]

Iustin Pop-2 wrote:

What filesystem are you using?

regards,
iustin

I WAS using the ext3 filesystem.  After posting this I started looking for sync problems with ext3 and ext2 filesystems even though I wasn't using ext2.  One topic came up and the guy had the same exact problem.  Anyway the result of the post was that ext3 is not a shared filesystem and he had to use one of a specific list of shared filesystems in order for it to work.  It makes sense that it will not work with ext3.

A list of shared filesystems and block devices were listed:

Shared Block Devices:
   SAN
   Dual attached SCSI
   GNBD
   DRBD
   iSCSI

Shared Filesystem:
   gfs
   gfs2
   gpfs
   ocfs
   ocfs2

I choose to go with the ocfs2 filesystem and found a complete guide to setting it up with my current configuration of DRBD without having to invalidate all my data on the second machine and resync.  Here is a link to the guide http://www.drbd.org/users-guide/ch-ocfs2.html

Just for the record my problem is solved, thank you guys.  For anyone else that comes across this I hope the information above suffices for a resolution for your problem.

[Martin Gombac(]

Be careful, by default, creating a new filesystem is destructive operation.

Regards,
M.

dascione wrote:

>
> Iustin Pop-2 wrote:
>> What filesystem are you using?
>>
>> regards,
>> iustin
>>
>
> I WAS using the ext3 filesystem.  After posting this I started looking for
> sync problems with ext3 and ext2 filesystems even though I wasn't using
> ext2.  One topic came up and the guy had the same exact problem.  Anyway the
> result of the post was that ext3 is not a shared filesystem and he had to
> use one of a specific list of shared filesystems in order for it to work.
> It makes sense that it will not work with ext3.
>
> A list of shared filesystems and block devices were listed:
>
> Shared Block Devices:
>    SAN
>    Dual attached SCSI
>    GNBD
>    DRBD
>    iSCSI
>
> Shared Filesystem:
>    gfs
>    gfs2
>    gpfs
>    ocfs
>    ocfs2
>
> I choose to go with the ocfs2 filesystem and found a complete guide to
> setting it up with my current configuration of DRBD without having to
> invalidate all my data on the second machine and resync.  Here is a link to
> the guide http://www.drbd.org/users-guide/ch-ocfs2.html
>
> Just for the record my problem is solved, thank you guys.  For anyone else
> that comes across this I hope the information above suffices for a
> resolution for your problem.
>

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