Hi Daniel, No need to pardon if you are asking question to learn something new. These questions helps us a lot to refine our documentation, as its not yet ready. I will try to answer your question inline with your mail. > > Pardon my (clearly newbie) question, but what are the namespace bricks > for, exactly ? I see that they are present in almost every example on > the wiki, but having read a great deal of the documentation, i'm > still fuzzy on exactly what this brick does, and how it incorporates > into the storage definitions. Hope this link gives a small idea about namespace. http://www.gluster.org/docs/index.php/Understanding_Unify_Translator#Namespace_FAQ As its a _must_ need part of unify translator, its present in all the examples. Also, in the "Install_and_run_GlusterFS_v1.3_in_10mins" wiki article, > the "Example 2 [3 servers, single client]" server config example > contains this rather ominous warning : > # Note: Once exported, DO NOT WRITE DIRECTLY TO THIS DIRECTORY > > This, of course, relates to the "volume brick" definition, which > exports "/tmp/export" on each server. Why shouldn't we write to this > directory after it has been exported ? Does it have something to do > with the namespace, perhaps ? > Its not related to 'namespace', but a general practice when using GlusterFS. We _advice_ you not to write directly into exported directory because, it may create problems when you use encryption translator, or stripe translator etc. While using unify, you can export a directory which already has data, or write directly to backend, but this will cause a bit of performance overhead for GlusterFS as it has to rebuild (or in our terms self-heal) the namespace volume. Hence, that note in the example. > > If the server generates some data which needs to be in the volume, and > it can't (as per the warning) write directly to /tmp/export, how should > it write the data to the volume instead ? > Server can also use glusterfs mountpoint, and write through that. > > Thank you all for your helpful responses thus far. > > > -- > Daniel Maher <dma AT witbe.net> > > -- Amar Tumballi Gluster/GlusterFS Hacker [bulde on #gluster/irc.gnu.org] http://www.zresearch.com - Commoditizing Supercomputing and Superstorage!
