<div dir="ltr"><div class="gmail_default" style="font-family:verdana,sans-serif">I see the Manual Failover section of the DRBD 8.4.x manual, and I see that it requires that the file system be umounted before attempting to promote and mount the file system on the secondary. <br><br>What I meant by "those status flags" in my first message is that when a node mounts a file
system, that file system is marked as mounted somewhere on that
device. The "mounted" status flag is what I'm trying to describe, and
I'm not sure if I have the correct name for it. <br><br></div><div class="gmail_default" style="font-family:verdana,sans-serif">Does pacemaker or manual failover handle the case where a file server experiences a hard failure where the umount operation is impossible? How can the secondary copy of the file system be mounted if the umount operation never occurred and cannot occur on server1?<br><br></div><div class="gmail_default" style="font-family:verdana,sans-serif"><br></div></div><div class="gmail_extra"><br clear="all"><div><div class="gmail_signature" data-smartmail="gmail_signature"><div dir="ltr"><div><div dir="ltr"><div>-James Ault, <a href="http://www.linkedin.com/in/aultj/" target="_blank">http://www.linkedin.com/in/aultj/</a> <a href="http://tinyurl.com/link2jimault" target="_blank">http://tinyurl.com/link2jimault </a><br></div><div><a href="http://www.bornofthespirit.today/" target="_blank">Life's Biggest Decision is...</a><br></div><div><br></div></div></div></div></div></div>
<br><div class="gmail_quote">On Thu, Jul 7, 2016 at 10:48 AM, Lars Ellenberg <span dir="ltr"><<a href="mailto:lars.ellenberg@linbit.com" target="_blank">lars.ellenberg@linbit.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div class="HOEnZb"><div class="h5">On Thu, Jul 07, 2016 at 07:16:51AM -0400, James Ault wrote:<br>
> Here is a scenario:<br>
><br>
> Two identical servers running RHEL 6.7,<br>
> Three RAID5 targets, with one Logical volume group and one logical volume<br>
> defined on top of each target.<br>
> A DRBD device defined on top of each logical volume, and then an XFS file<br>
> system defined on top of each DRBD device.<br>
><br>
> The two identical servers are right on top of one another in the rack, and<br>
> connected by a single ethernet cable for a private network.<br>
><br>
> The configuration works as far as synchronization between DRBD devices.<br>
><br>
> We do NOT have pacemaker as part of this configuration at management's<br>
> request.<br>
><br>
> We have the XFS file system mounted on server1, and this file system is<br>
> exported via NFS.<br>
><br>
> The difficulty lies in performing failover actions without pacemaker<br>
> automation.<br>
><br>
> The file system is mounted, and those status flags on the file system are<br>
> successfully mirrored to server2.<br>
><br>
> If I disconnected all wires from server1 to simulate system failure, and<br>
> promoted server2 to primary on one of these file systems, and attempted to<br>
> mount it, the error displayed is "file system already mounted".<br>
><br>
> I have searched the xfs_admin and mount man pages thoroughly to find an<br>
> option that would help me overcome this state.<br>
><br>
> Our purpose of replication is to preserve and recover data in case of<br>
> failure, but we are unable to recover or use the secondary copy in our<br>
> current configuration.<br>
><br>
> How can I recover and use this data without introducing pacemaker to our<br>
> configuration?<br>
<br>
</div></div>If you want to do manual failover (I believe we have that also<br>
documented in the User's Guide), all you do is<br>
<br>
drbdadm primary $res<br>
mount /dev/drbdX /some/where<br>
<br>
That's also exactly what pacemaker would do.<br>
<br>
If that does not work,<br>
you have it either "auto-mounted" already by something,<br>
or you have some file system UUID conflict,<br>
or something else is very wrong.<br>
<span class="HOEnZb"><font color="#888888"><br>
<br>
--<br>
: Lars Ellenberg<br>
: LINBIT | Keeping the Digital World Running<br>
: DRBD -- Heartbeat -- Corosync -- Pacemaker<br>
<br>
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</font></span></blockquote></div><br></div>