Unexplained Multiple Lauches of Script with NetBackup ... could it be PERL?

J

Jay W

I have a PERL script that is executed by NetBackup "bpstart". From within
the script two different lines are launched depending on the Policy passed
to bpstart in %2. Only one of the two lines should be launched at any given
time.

The problem is that shortly after launching the script (about 5 minutes), a
second occurrance starts, then a 3rd, then a 4th .... up to 29 occurances in
some cases. Usually this scenario ends with a Dr Watson abort. The odd thing
is that I use about 7 command line parameters that are identical in each
launch, so a full command line is being "re-executed" :

function: Perl_dounwind
280363f1 b903010000 mov ecx,0x103
280363f6 7417 jz Perl_sv_compile_2op+0x6fa0
(2803ef0f)

*----> Stack Back Trace <----*

FramePtr ReturnAd Param#1 Param#2 Param#3 Param#4 Function Name
0140FD9C 2805D784 01B31308 015D41C4 28024499 015D41C4 !Perl_dounwind
0140FE24 280862DE 015D41C4 00000000 00000000 505C3A43 !Perl_runops_standard
0140FF3C 00401012 0000000C 015D24B0 015D2AF8 004010F9 !RunPerl
0140FFC0 77E9CA90 00000000 00000000 7FFDF000 C0000005 !<nosymbols>
0140FFF0 00000000 00401016 00000000 000000C8 00000100
kernel32!CreateProcessW

I guess, the questions are :

1. Has anyone else run into this?
2. Is there a syntax that may inadvertantly start another instance of the
command that was originally launched? (I'm 1st year PERL)

I'm trying to prove through debug code that it is NetBackup's fault and not
PERL

Env :

W2K AS - SP4
ActiveState PERL 5.8.1
 
W

Walt Mankowski

I have a PERL script that is executed by NetBackup "bpstart". From within
the script two different lines are launched depending on the Policy passed
to bpstart in %2. Only one of the two lines should be launched at any given
time.

The problem is that shortly after launching the script (about 5 minutes), a
second occurrance starts, then a 3rd, then a 4th .... up to 29 occurances in
some cases. Usually this scenario ends with a Dr Watson abort. The odd thing
is that I use about 7 command line parameters that are identical in each
launch, so a full command line is being "re-executed" :

function: Perl_dounwind
280363f1 b903010000 mov ecx,0x103
280363f6 7417 jz Perl_sv_compile_2op+0x6fa0
(2803ef0f)

*----> Stack Back Trace <----*

FramePtr ReturnAd Param#1 Param#2 Param#3 Param#4 Function Name
0140FD9C 2805D784 01B31308 015D41C4 28024499 015D41C4 !Perl_dounwind
0140FE24 280862DE 015D41C4 00000000 00000000 505C3A43 !Perl_runops_standard
0140FF3C 00401012 0000000C 015D24B0 015D2AF8 004010F9 !RunPerl
0140FFC0 77E9CA90 00000000 00000000 7FFDF000 C0000005 !<nosymbols>
0140FFF0 00000000 00401016 00000000 000000C8 00000100
kernel32!CreateProcessW

I guess, the questions are :

1. Has anyone else run into this?
2. Is there a syntax that may inadvertantly start another instance of the
command that was originally launched? (I'm 1st year PERL)

I'm trying to prove through debug code that it is NetBackup's fault and not
PERL

Env :

W2K AS - SP4
ActiveState PERL 5.8.1

If the problem is on the Perl end and not the NetBackup end, it's much
more likely that it's something in the script and not the Perl
executable itself. What's your script doing? Is it maybe doing
something like fork or system that would kick off another process?

Walt
 
J

James Willmore

Jay W said:
I have a PERL script that is executed by NetBackup "bpstart". From within
the script two different lines are launched depending on the Policy passed
to bpstart in %2. Only one of the two lines should be launched at any given
time.

What is "bpstart" supposed to do? What does it have to do with Perl?
The problem is that shortly after launching the script (about 5 minutes), a
second occurrance starts, then a 3rd, then a 4th .... up to 29 occurances in
some cases. Usually this scenario ends with a Dr Watson abort. The odd thing
is that I use about 7 command line parameters that are identical in each
launch, so a full command line is being "re-executed" :
<snip>

Is it a Perl script that is executed and then re-executed? I guess
we're back to the first question - what is "bpstart" supposed to do?
and What does it have to do with Perl?
I guess, the questions are :

1. Has anyone else run into this?

No. Right now where I work we use Syncsort's Backup Express, but will
be using a Veritas product in the future. I'm drawing upon my
experience with Backup Express on this, but ... is "bpstart" supposed
to start a backup? If so, is your Perl script a pre-backup script
that's supposed to run? Maybe take down a database or kill a process?
If so, then it may be "bpstart that's starting these numerious
instances of Perl. Again, this is a guess.
2. Is there a syntax that may inadvertantly start another instance of the
command that was originally launched? (I'm 1st year PERL)

Usless you have a 'system' call to start another script or are using
threads in some strange fashion, no. The invocation of a Perl script
will _not_ cause another invocation of the same script unless you tell
the script to do so. However, if this "bpstart" application is
supposed to start numerious times, then it may be starting numerious
instances of the script. Again ... answer the first two questions to
shed more light on this.
I'm trying to prove through debug code that it is NetBackup's fault and not
PERL
<snip>

Just some suggestions ....
1) depending upon what your script is trying to do, you could put in
some 'alarm's to kill the script after a certain period of time.
2) use some type of lock file scheme to prevent and detect the script
being started a second time. The LockFile::Simple module _may_ be
able to aid in this.
3) put in some logging code -or- use a logging module to see what the
script is doing, when it's doing it, etc. Log::Dispatch and other
modules may fit the bill for your purposes.

You need to provide some _more_ information than what you did. What
you provided was not very specific except that there is an issue and
you're not sure what it is. Some code would help, as well as
answering some of the questions earlier in the post.

HTH

Jim
 

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