This is a good example. I do not know whether there are other cases, but for this case, I'd like another design: Add a parameter to guide glusterfs to double-check whether the bricks are mount points when creating or starting a volume.
------------------ Original ------------------
From: "Claudio Kuenzler";<ck@xxxxxxxxxxxxxxxxxxx>;
Date: Sep 12, 2014
To: "Juan José Pavlik Salles"<jjpavlik@xxxxxxxxx>;
Cc: "gluster-users"<gluster-users@xxxxxxxxxxx>; "Paul Guo"<bigpaulguo@xxxxxxxxxxx>;
Subject: Re: [Gluster-users] error when using mount point as a brick directory.
On the other side I am thankful for the error/warning which prevented me to create the volume because I just thought of a scenario which could result in problems.
Imagine you have a LV you want to use for the gluster volume. Now you mount this LV to /mnt/gluster1. You do this on the other host(s), too and you create the gluster volume with /mnt/gluster1 as brick.
By mistake you forget to add the mount entry to fstab so the next time you reboot server1, /mnt/gluster1 will be there (because it's the mountpoint) but the data is gone (because the LV is not mounted).
I don't know how gluster would handle that but it's actually easy to try it out :)
So using a subfolder within the mountpoint makes sense, because that subfolder will not exist when the mount of the LV didn't happen.
On Sep 12, 2014 4:16 PM, "Juan José Pavlik Salles" <jjpavlik@xxxxxxxxx> wrote:
Maybe it's not a warning, but you can use "force" to avoid that behaviour so it's not that you can't create the volume. Anyway, it's a good practice to create a subdirectory as far as I've read.
2014-09-12 11:02 GMT-03:00 Claudio Kuenzler <ck@xxxxxxxxxxxxxxxxxxx>:
Hi
On Fri, Sep 12, 2014 at 3:00 PM, Juan José Pavlik Salles <jjpavlik@xxxxxxxxx> wrote:
Hi Paul, that's is more a warning than an error. This advice helps you avoid situations like this:
Not so sure if it's "only a warning". The volume cannot be created as long as the fs mountpoint is directly used as brick in "gluster volume create".
I wrote a post about that last month: http://www.claudiokuenzler.com/blog/499/glusterfs-bricks-should-be-subfolder-of-mountpoint
But as long as it is documented I don't think it's a real issue to follow that rule.
--
Pavlik Salles Juan José
Blog - http://viviendolared.blogspot.com
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