Re: Stracing Amanda (was: RSDL for 2.6.21-rc3- 0.29)
On Tuesday 13 March 2007, Willy Tarreau wrote:
>On Tue, Mar 13, 2007 at 12:04:42AM -0400, Gene Heskett wrote:
>> On Monday 12 March 2007, Nish Aravamudan wrote:
>> >On 3/12/07, Gene Heskett <[EMAIL PROTECTED]> wrote:
>> >> On Monday 12 March 2007, Douglas McNaught wrote:
>> >> >Patrick Mau <[EMAIL PROTECTED]> writes:
>> >> >> Why not temporarly replace "/bin/tar" with a shell script that
>> >> >> does:
>> >> >>
>> >> >> #!/bin/sh
>> >> >> exec strace -f -o output /bin/real.tar $@
>> >> >
>> >> >You beat me to it. :) I've done that before; it's a great
>> >> > suggestion.
>> >> >
>> >> >Except that if you expect 'tar' to be invoked multiple times in a
>> >> > run, you should probably use 'output.$$' for the output filename
>> >> > so things don't get clobbered.
>> >> >
>> >> >-Doug
>> >>
>> >> In my case, Doug, it will get invoked 64 times, amanda does a dummy
>> >> run to get an estimate, calculates what to do based on that output
>> >> which is 32 runs, 1 per disklist entry and I have 32, and then
>> >> reruns tar with the appropriate level options against each
>> >> individual disklist entry.
>> >>
>> >> But I'm puzzled a bit, what does the double $$ do?, or it buried
>> >> someplace in the bash manpage? Its not something I've stumbled
>> >> over yet.
>> >
>> >buried indeed:
>> >
>> >"Special Parameters:
>> > ...
>> > $ Expands to the process ID of the shell. In a ()
>> > subshell, it expands to the process ID of the current shell,
>> > not the sub?$B!> shell.
>> >"
>>
>> Well, that's clear enough, but what of the double $$ case? Would this
>> them make a PID unique to each invocation untill it finally wraps a 16
>> bit value, or will the kernel re-use them because they won't all be
>> running simultainiously, but limited by the number of unique 'spindle'
>> numbers on the system, this to prevent as best as it can, the
>> thrashing of a drive by having tar working on 2 separate (or more)
>> partitions at the same time. In my case 2 are possible, as /var is on
>> a separate drive.
>
>Yes there a risk of wrapping, but it is very small. You can add the
> command line arguments to the file name if you want, like this :
>
>#!/bin/sh
>exec strace -f -o "output.$$.${*//\//_}" /bin/real.tar $@
>
>It will name the output file "output..", replacing slashes
> with underscores. This is very dirty but can help.
>
Excellent Willy, thanks.
>Cheers,
>Willy
--
Cheers, Gene
"There are four boxes to be used in defense of liberty:
soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author)
Whatever doesn't succeed in two months and a half in California will
never succeed.
-- Rev. Henry Durant, founder of the University of California
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Re: Stracing Amanda (was: RSDL for 2.6.21-rc3- 0.29)
On Tue, Mar 13, 2007 at 12:04:42AM -0400, Gene Heskett wrote:
> On Monday 12 March 2007, Nish Aravamudan wrote:
> >On 3/12/07, Gene Heskett <[EMAIL PROTECTED]> wrote:
> >> On Monday 12 March 2007, Douglas McNaught wrote:
> >> >Patrick Mau <[EMAIL PROTECTED]> writes:
> >> >> Why not temporarly replace "/bin/tar" with a shell script that
> >> >> does:
> >> >>
> >> >> #!/bin/sh
> >> >> exec strace -f -o output /bin/real.tar $@
> >> >
> >> >You beat me to it. :) I've done that before; it's a great
> >> > suggestion.
> >> >
> >> >Except that if you expect 'tar' to be invoked multiple times in a
> >> > run, you should probably use 'output.$$' for the output filename so
> >> > things don't get clobbered.
> >> >
> >> >-Doug
> >>
> >> In my case, Doug, it will get invoked 64 times, amanda does a dummy
> >> run to get an estimate, calculates what to do based on that output
> >> which is 32 runs, 1 per disklist entry and I have 32, and then reruns
> >> tar with the appropriate level options against each individual
> >> disklist entry.
> >>
> >> But I'm puzzled a bit, what does the double $$ do?, or it buried
> >> someplace in the bash manpage? Its not something I've stumbled over
> >> yet.
> >
> >buried indeed:
> >
> >"Special Parameters:
> > ...
> > $ Expands to the process ID of the shell. In a ()
> > subshell, it expands to the process ID of the current shell, not
> > the sub?$B!> shell.
> >"
>
> Well, that's clear enough, but what of the double $$ case? Would this
> them make a PID unique to each invocation untill it finally wraps a 16
> bit value, or will the kernel re-use them because they won't all be
> running simultainiously, but limited by the number of unique 'spindle'
> numbers on the system, this to prevent as best as it can, the thrashing
> of a drive by having tar working on 2 separate (or more) partitions at
> the same time. In my case 2 are possible, as /var is on a separate
> drive.
Yes there a risk of wrapping, but it is very small. You can add the command
line arguments to the file name if you want, like this :
#!/bin/sh
exec strace -f -o "output.$$.${*//\//_}" /bin/real.tar $@
It will name the output file "output..", replacing slashes with
underscores. This is very dirty but can help.
Cheers,
Willy
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to [EMAIL PROTECTED]
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
Re: Stracing Amanda (was: RSDL for 2.6.21-rc3- 0.29)
On Monday 12 March 2007, Nish Aravamudan wrote: >On 3/12/07, Gene Heskett <[EMAIL PROTECTED]> wrote: >> On Monday 12 March 2007, Douglas McNaught wrote: >> >Patrick Mau <[EMAIL PROTECTED]> writes: >> >> Why not temporarly replace "/bin/tar" with a shell script that >> >> does: >> >> >> >> #!/bin/sh >> >> exec strace -f -o output /bin/real.tar $@ >> > >> >You beat me to it. :) I've done that before; it's a great >> > suggestion. >> > >> >Except that if you expect 'tar' to be invoked multiple times in a >> > run, you should probably use 'output.$$' for the output filename so >> > things don't get clobbered. >> > >> >-Doug >> >> In my case, Doug, it will get invoked 64 times, amanda does a dummy >> run to get an estimate, calculates what to do based on that output >> which is 32 runs, 1 per disklist entry and I have 32, and then reruns >> tar with the appropriate level options against each individual >> disklist entry. >> >> But I'm puzzled a bit, what does the double $$ do?, or it buried >> someplace in the bash manpage? Its not something I've stumbled over >> yet. > >buried indeed: > >"Special Parameters: > ... > $ Expands to the process ID of the shell. In a () > subshell, it expands to the process ID of the current shell, not > the sub‐ shell. >" Well, that's clear enough, but what of the double $$ case? Would this them make a PID unique to each invocation untill it finally wraps a 16 bit value, or will the kernel re-use them because they won't all be running simultainiously, but limited by the number of unique 'spindle' numbers on the system, this to prevent as best as it can, the thrashing of a drive by having tar working on 2 separate (or more) partitions at the same time. In my case 2 are possible, as /var is on a separate drive. >Thanks, >Nish -- Cheers, Gene "There are four boxes to be used in defense of liberty: soap, ballot, jury, and ammo. Please use in that order." -Ed Howdershelt (Author) "Say yur prayers, yuh flea-pickin' varmint!" -- Yosemite Sam - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: Stracing Amanda (was: RSDL for 2.6.21-rc3- 0.29)
On 3/12/07, Gene Heskett <[EMAIL PROTECTED]> wrote: On Monday 12 March 2007, Douglas McNaught wrote: >Patrick Mau <[EMAIL PROTECTED]> writes: >> Why not temporarly replace "/bin/tar" with a shell script that does: >> >> #!/bin/sh >> exec strace -f -o output /bin/real.tar $@ > >You beat me to it. :) I've done that before; it's a great suggestion. > >Except that if you expect 'tar' to be invoked multiple times in a run, >you should probably use 'output.$$' for the output filename so things >don't get clobbered. > >-Doug In my case, Doug, it will get invoked 64 times, amanda does a dummy run to get an estimate, calculates what to do based on that output which is 32 runs, 1 per disklist entry and I have 32, and then reruns tar with the appropriate level options against each individual disklist entry. But I'm puzzled a bit, what does the double $$ do?, or it buried someplace in the bash manpage? Its not something I've stumbled over yet. buried indeed: "Special Parameters: ... $ Expands to the process ID of the shell. In a () subshell, it expands to the process ID of the current shell, not the sub‐ shell. " Thanks, Nish - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: Stracing Amanda (was: RSDL for 2.6.21-rc3- 0.29)
On Monday 12 March 2007, Douglas McNaught wrote: >Patrick Mau <[EMAIL PROTECTED]> writes: >> Why not temporarly replace "/bin/tar" with a shell script that does: >> >> #!/bin/sh >> exec strace -f -o output /bin/real.tar $@ > >You beat me to it. :) I've done that before; it's a great suggestion. > >Except that if you expect 'tar' to be invoked multiple times in a run, >you should probably use 'output.$$' for the output filename so things >don't get clobbered. > >-Doug In my case, Doug, it will get invoked 64 times, amanda does a dummy run to get an estimate, calculates what to do based on that output which is 32 runs, 1 per disklist entry and I have 32, and then reruns tar with the appropriate level options against each individual disklist entry. But I'm puzzled a bit, what does the double $$ do?, or it buried someplace in the bash manpage? Its not something I've stumbled over yet. -- Cheers, Gene "There are four boxes to be used in defense of liberty: soap, ballot, jury, and ammo. Please use in that order." -Ed Howdershelt (Author) rugged, adj.: Too heavy to lift. - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Stracing Amanda (was: RSDL for 2.6.21-rc3- 0.29)
Patrick Mau <[EMAIL PROTECTED]> writes: > Why not temporarly replace "/bin/tar" with a shell script that does: > > #!/bin/sh > exec strace -f -o output /bin/real.tar $@ You beat me to it. :) I've done that before; it's a great suggestion. Except that if you expect 'tar' to be invoked multiple times in a run, you should probably use 'output.$$' for the output filename so things don't get clobbered. -Doug - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
