<html><body style="font-family: 'Helvetica Neue',Helvetica,Arial,sans-serif; font-size: 12px;">Dear Daniel, <br /><div><br /></div><div>Noticing references in the manual without explanation, I had spent quite some time on search engines trying to understand nonode@nohost.</div><div><br /></div><div>It is starting to make sense now i have read your answer.</div><div><br /></div><div>Thank you, Daniel !</div><div><br /></div><div>Happy coding,</div><div>Peter<br /></div><blockquote><br />----- Original Message -----<br /><div style="width:100%;background:rgb(228,228,228);"><div style="font-weight:bold;">From:</div> "Dániel Szoboszlay" <dszoboszlay@gmail.com></div><br /><div style="font-weight:bold;">To:</div>"Peter J Etheridge" <petergi@iinet.net.au><br /><div style="font-weight:bold;">Cc:</div>"erlang-questions" <erlang-questions@erlang.org><br /><div style="font-weight:bold;">Sent:</div>Thu, 11 Jul 2019 23:30:44 +0200<br /><div style="font-weight:bold;">Subject:</div>Re: [erlang-questions] Mnesia folder<br /><br /><br /><div dir="ltr">This directory was created because you once called <font face="courier new, monospace">mnesia:create_schema/1</font> on a node called <font face="courier new, monospace">nonode@nohost</font> (that is, on a non-distributed node).<div><br /></div><div>By the way, <span style="font-family:'courier new', monospace;">nonode@nohost</span> is not really an error, per se. Every Erlang node has a name (see <font face="courier new, monospace"><a href="http://erlang.org/doc/man/erlang.html#node-0">erlang:node/0</a></font>). For distributed nodes the name is important, because other nodes can find and connect to it via its name. But there can be non-distributed nodes too. They don't listen to incoming connections and don't attempt to connect to other nodes either. So their name is completely irrelevant, and by definition they are always called <span style="font-family:'courier new', monospace;">nonode@nohost</span>. (It is also possible to <a href="http://erlang.org/doc/man/net_kernel.html#stop-0">stop</a> and <a href="http://erlang.org/doc/man/net_kernel.html#start-1">start</a> distribution on a node without stopping it. If you do so, it will change its name.)</div><div><br /></div><div>Now, the documentation sometimes calls nodes where distribution is running "<i>alive</i>, and nodes where it is stopped "<i>not alive"</i>. These names may be a bit confusing. A "not alive" node is still alive in the sense that it is running and executing code. It is just not accessible to other nodes via the Erlang distribution protocol.</div><div><br /></div><div>Back to Mnesia: Mnesia allows you to create a distributed database, but it can work perfectly on a single node as well. So it's even valid to use Mnesia on a non-distributed node. If you do so, you will get the directory you found. Of course, if you no longer want to use non-distributed nodes and don't need this DB instance, you can just delete it now.</div><div><br /></div><div>Cheers,</div><div>Daniel</div></div><br /><div class="gmail_quote"><div dir="ltr" class="gmail_attr">On Thu, 11 Jul 2019 at 07:39, Peter J Etheridge <<a href="mailto:petergi@iinet.net.au">petergi@iinet.net.au</a>> wrote:<br /></div><blockquote class="gmail_quote" style="margin:0px 0px 0px .8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex;"><div style="font-family:'Helvetica Neue', Helvetica, Arial, sans-serif;font-size:12px;"><div>dear list,</div><div>having recently discovered that nonode@nohost is an error, i now find a folder;</div><div><br /></div><div>Mnesia.nonode@nohost</div><div><br /></div><div>containing files;</div><div><br /></div><div>DECISION_TAB.LOG</div><div>LATEST.LOG</div><div>etc</div><div><br /></div><div>could this be because i did not name my node?</div><div><br /></div><div>thank you in advance,</div><div>peter<br /></div><br /><br /></div>
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