Yes should be possible except when I (and Ulf :-) mess things up, which we did in mnesia-4.4.19. <div>In which mnesia couldn't talk to older versions.</div><div><br></div><div>I don't think that is not your problem here:</div>
<div>You have two different versions of the schema content here: </div><div>old:  <span style="font-family:arial,sans-serif;font-size:12.727272033691406px">{version,{{4,0},{'ejabberd@</span><span style="font-family:arial,sans-serif;font-size:12.727272033691406px">new.dev',{1355,182745,138103}}</span></div>
<div><span style="font-family:arial,sans-serif;font-size:12.727272033691406px">new: </span><span style="font-family:arial,sans-serif;font-size:12.727272033691406px">{version,{{5,0},{'ejabberd@</span><span style="font-family:arial,sans-serif;font-size:12.727272033691406px">new.dev',{1355,182745,345805}}</span></div>
<div><span style="font-family:arial,sans-serif;font-size:12.727272033691406px"><br></span></div><div><span style="font-family:arial,sans-serif;font-size:12.727272033691406px">Mnesia will not allow them to be merged, you have done something with the table def before the merge.</span></div>
<div><span style="font-family:arial,sans-serif;font-size:12.727272033691406px"><br></span></div><div><span style="font-family:arial,sans-serif;font-size:12.727272033691406px">/Dan</span></div><div class="gmail_extra"><br>
<br><div class="gmail_quote">On Tue, Dec 11, 2012 at 1:12 AM, Daniel Dormont <span dir="ltr"><<a href="mailto:dan@greywallsoftware.com" target="_blank">dan@greywallsoftware.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
Hey gang,<br>
<br>
Is it possible and/or safe to run a Mnesia cluster across two Erlang<br>
nodes running different releases? In particular I have one node on<br>
R14B04 and another on R13B03, and when I tried to set up a cluster I<br>
got this rather nasty error:<br>
<br>
** FATAL ** Failed to merge schema: Incompatible schema storage types<br>
(remote). on 'ejabberd@old.dev' cs<br>
 [{name,schema},{type,set},{ram_copies,['ejabberd@new.dev']},{disc_copies,['ejabberd@old.dev']}<br>
 ,{disc_only_copies,[]},{load_order,0},{access_mode,read_write},{index,[]},{snmp,[]},{local_content,false},{record_name,schema},<br>
 {attributes,[table,cstruct]},{user_properties,[]},{frag_properties,[]},{cookie,{{1351,554882,753639},'ejabberd@old.dev'}},<br>
 {version,{{4,0},{'ejabberd@new.dev',{1355,182745,138103}}}}],<br>
 on 'ejabberd@new.dev' rcs<br>
[{name,schema},{type,set},{ram_copies,[]},{disc_copies,['ejabberd@new.dev','ejabberd@old.dev']},<br>
 {disc_only_copies,[]},{load_order,0},{access_mode,read_write},{index,[]},{snmp,[]},{local_content,false},{record_name,schema},{attributes,[table,cstruct]},<br>
 {user_properties,[]},{frag_properties,[]},{cookie,{{1351,554882,753639},'ejabberd@old.dev'}},<br>
 {version,{{5,0},{'ejabberd@new.dev',{1355,182745,345805}}}}]<br>
<br>
But I wonder if there was something else wrong in my cluster<br>
configuration that caused this.<br>
<br>
thanks,<br>
Dan<br>
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</blockquote></div><br></div>