[Halld-offline] CCDB server confusion

[Mark M. Ito]

Sean,

Undocumented feature, I'm afraid...sorry...

There really are two servers. Outside the lab, hallddb.jlab.org resolves 
to a server that, as you can tell, is accessible via mysql on the 
standard port. Inside the lab, hallddb.jlab.org resolves to 
halldweb1.jlab.org (one node, runs both webserver and db server). The 
outward facing server gets updated nightly, but is read-only, enforced 
via the native mysql access control. That way anyone can see our 
calibration constants but no one can change them. The one inside the lab 
is the "real" one, obviously.

So we are protected only by the lab's standard login protection; anyone 
that can log in to JLab can change the database. We record all of the 
history in the database itself and have a backup scheme. These gives us 
some protection against inadvertent changes coming from JLab users, most 
likely GlueX collaborators. Note further that if you use a time 
specification when requesting constants, you are completely immune to 
changes.

The update of the outward facing server happens at midnight, so changes 
made on the inside are not instantly available on the outside.

The advantage is that the same CCDB_CONNECTION environment variable 
works both inside and outside the lab, unless you want to write. The 
disadvantage is that it is confusing to experts. It borders on being a 
bit too clever, I admit.

This may change as we re-arrange the servers in the near future. In 
particular, we will almost certainly have an independent database server 
on the inside.

   -- Mark

On 05/15/2014 04:09 PM, Sean Dobbs wrote:
> Hi Mark,
>
> I've been playing around the constants a bit today, and am a bit 
> confused about which server I should be accessing.  This came up since 
> I noticed that on the CUE, when I try to look up the location of 
> hallddb.jlab.org <http://hallddb.jlab.org>, I get this:
>
> ifarm1101> host hallddb.jlab.org <http://hallddb.jlab.org>
> hallddb.jlab.org <http://hallddb.jlab.org> is an alias for 
> halldweb1.jlab.org <http://halldweb1.jlab.org>.
> halldweb1.jlab.org <http://halldweb1.jlab.org> has address 129.57.64.28
>
> But at NU, I get the following mapping:
>
> hallddb.jlab.org <http://hallddb.jlab.org> -> 129.57.52.40
> halldweb1.jlab.org <http://halldweb1.jlab.org> -> 129.57.64.28
>
> I remember that awhile back you moved some servers around, so I'm not 
> sure if this is a DNS problem or not.  Can you remind me which is the 
> right place to access?  (side note: I can get at the CCDB 
> in 129.57.64.28 just fine on the ifarm, but not from NU).
>
>
> Cheers,
> Sean
>
> -- 
> Sean Dobbs
> Department of Physics & Astronomy
> Northwestern University
> phone: 847-467-2826

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