Hi all,

This is the first time to write you. As part of my master's thesis at
Budapest University I should simulate the key functions of VCL with
CloudSim.

For that the allocating logic is very important part means how a computer
is assigned to a reservation. I checked the cwiki page of VCL but the exact
procedure is not published. I've started to look inside the code and found
the predictive levels in PERL modules and it was understandable thanks to
vcld.log file which helped me to backtrace when, how and who called thoose
functions.

Unfortunately this is not enough because the logic is missing how a
computer will be assigned to an image/reservation. As I saw this allocating
happens in Request.php (fn newReservation()) and maybe the main logic is in
Utils.php (fn allocComputer). My problem is that there is no log that I can
use to backtrace what and when happening and I don't understand how this
allocating works. Some questions: Is it random which available computer
will be used? If a computer is preloaded with the same image that a user
chose too then where and how will be taken this into account and filter
that computers which are preloaded with that image? What happens if a user
requests such an image that is not preloaded on any computer, is it problem
or only the provisioning time period will last a bit more?

Can someone explain the logic behind the allocating procedure and tell me
how the "computer-id" value of reservations table is calculated?

Can you recommend me some technique to trace the "happenings" in php
scripts? I tried to use Zend Server instead of php5 server but there is
something wrong. Have you tried to use it with Zend Server, any
documentation or it shouldn't be problem?

Thank you in advance!

Best regards,
Norbert

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