[Gluster-users] Docs on setting up translators

[Joel Young]

On Thu, Aug 1, 2013 at 8:59 AM, Jeff Darcy <jdarcy at redhat.com> wrote:
> Options set via the Gluster CLI are both global (for the volume) and
> persistent.  You shouldn't need to know which actual file(s) the changes go
> into, because the fetching and use of those files is automatic as part of
> volume startup (on the server side) or mounting (on the client side).
>
> Joel gushed:
>> For example it says "The IO-Cache translator is useful on both the client
>> and server sides of a connection."  Great!  How?  How do I specify that I
>> want it on the client side? How do I specify which client?  How do I check
>> to see if the change has "taken"?
>
On Thu, Aug 1, 2013 at 8:59 AM, Jeff Darcy <jdarcy at redhat.com> wrote:
> Yes, that particular piece of documentation seems rather useless.  While
> translators *can* be loaded and even be beneficial on either side, the CLI
> tends to treat them as server-only or client-only.  The reason is simply
> that if we supported every possible ordering and placement of translators
> we'd never be able to finish testing.  In this case, io-cache is loaded only
> on the client side and the doc should say so.

So looking at "Translator performance/io-threads" section I see a
snippet of configuration file (shown in violation of the philosophy
statement below).  Adapting from that I guess I should type:

"gluster volume set home performance.io-threads 32"

But a little lower in orange there is "thread-count Number of threads
to keep in the thread pool."  So I figure I should type:

"gluster volume set home performance.thread-count 32"

But then I check my self by looking at
http://gluster.org/community/documentation/index.php/Gluster_3.2:_Setting_Volume_Options
which I found by googling for "gluster volume set"

which shows "performance.io-thread-count" as the option available.
But is that current for 3.4.0?  Backing up the URL tree I find docs
for 3.3.0.  Digging in to these 3.3.0 docs which are only published as
a pdf or html tar ball at:
http://www.gluster.org/wp-content/uploads/2012/05/Gluster_File_System-3.3.0-Administration_Guide-en-US.pdf
it seems to still be correct then.  The admin guide doesn't seem to be
published for 3.4 so maybe it will work, maybe it won't.

What does it mean that "translators can be loaded"?  That statement
implies that I have to do an action to load a translator and then I
can set options.  I think that translators being loaded is something
that the user doesn't need to know about?  It is happening
automatically when an option is set or changed with gluster volume
set"?

I see on the devel list that there is a discussion about revamping the
docs.  Am I right that some of this language has been carried forward
from gluster 2.x days and isn't really quite accurate now?

> The philosophy is that other distributed filesystems (including
> GlusterFS 2.x) have done a more than adequate job demonstrating
> that configuration of such a system by manual hacking of config
> files on multiple machines doesn't scale and will drive users
> crazy.  Therefore, we assume responsibility for distribution,
> durability, and consistency of configuration info.  If you use the CLI,
> the "right" config files will be updated automatically, and since there
> are multiple machines holding copies of that information each can
> effectively be a backup for the others.  I know nobody ever believes
> that "you don't need to worry about that" but we do what we can
> to make it as true as possible.

Now that I like.

Thanks so much for your patience!

Joel