buggy tracker behavior?

[Mark Smith]

The 'verify' option (or rather, the lack of the noverify option) only
looks for one valid path.  Additionally, it randomizes based on the weights
of the devices.  So you end up with one of two scenarios: it tries the good
device first, or it tries the bad one first.

If it tries the good one, it says "hey, got a good device!" and it returns
both paths.  (No need to check the other one -- we've already verified one
of them!)  If it hits the bad one, then it has to throw it out, and then
return the other one.

If you notice from your output, the ONLY time you see both is when the
"good" device is listed as "path1" -- the first device it checked, and the
one that came out okay.

So no, not a bug.  Hope that makes sense.  :-)


-jr

On Thu, Feb 09, 2006, Drop Box wrote:
> Hi,
> 
> I'm testing out MogileFS and am getting some results from the tracker that I
> didn't expect.  I'm wondering whether it's a bug or a misunderstanding on my
> part.  I have a file saved to two devices on two different systems.  I
> unplugged one of the systems/devices (dev1 on .22) from the network and
> noticed that the tracker will sometimes respond to GET_PATHS with 2 paths,
> for some reason:
> 
> $ telnet localhost 7001
> Trying 127.0.0.1...
> Connected to localhost (127.0.0.1).
> Escape character is '^]'.
> GET_PATHS domain=test&key=thisismykey
> OK path2=http://192.168.0.22:7500/dev1/0/000/000/0000000054.fid&path1=http://192.168.0.23:7500/dev2/0/000/000/0000000054.fid&paths=2
> GET_PATHS domain=test&key=thisismykey
> OK path1= http://192.168.0.23:7500/dev2/0/000/000/0000000054.fid&paths=1
> GET_PATHS domain=test&key=thisismykey
> OK path2=http://192.168.0.22:7500/dev1/0/000/000/0000000054.fid&path1=http://192.168.0.23:7500/dev2/0/000/000/0000000054.fid&paths=2
> GET_PATHS domain=test&key=thisismykey
> OK path1= http://192.168.0.23:7500/dev2/0/000/000/0000000054.fid&paths=1
> GET_PATHS domain=test&key=thisismykey
> OK path2=http://192.168.0.22:7500/dev1/0/000/000/0000000054.fid&path1=http://192.168.0.23:7500/dev2/0/000/000/0000000054.fid&paths=2
> GET_PATHS domain=test&key=thisismykey
> OK path1= http://192.168.0.23:7500/dev2/0/000/000/0000000054.fid&paths=1
> GET_PATHS domain=test&key=thisismykey
> OK path1= http://192.168.0.23:7500/dev2/0/000/000/0000000054.fid&paths=1
> GET_PATHS domain=test&key=thisismykey
> OK path1=http://192.168.0.23:7500/dev2/0/000/000/0000000054.fid&paths=1
> GET_PATHS domain=test&key=thisismykey
> OK path2=http://192.168.0.22:7500/dev1/0/000/000/0000000054.fid&path1=http://192.168.0.23:7500/dev2/0/000/000/0000000054.fid&paths=2
> 
> 
> I would have guessed that GET_PATHS would only return the 1 available path,
> given that I'm not setting noverify.  Whether or not that's how it's
> supposed to work (could someone verify whether my guess is correct,
> though?), my knee-jerk reaction to the sporadic behavior is to think there's
> something wrong.  Thoughts?
> 
> I'm using the latest revision from CVS, btw.
> 
> Thanks.


--
Junior (aka Mark Smith)
junior at danga.com

Software Engineer
Six Apart / Danga Interactive