* [9fans] dd-induced hangs
@ 2003-07-07 22:05 andrey mirtchovski
2003-07-07 22:18 ` [9fans] " andrey mirtchovski
2003-07-07 22:26 ` [9fans] " David Presotto
0 siblings, 2 replies; 3+ messages in thread
From: andrey mirtchovski @ 2003-07-07 22:05 UTC (permalink / raw)
To: 9fans
doing 'dd -if /dev/sdC0/arenas -of /dev/sdD0/arenas -bs 8192' hangs the
system with 100% reproducibility (though each occurs after a different
period of time).
the arenas partition is 60GB. running the same command on smaller
partitions (fossil, 13GB; isect, 3GB; 9fat, 10MB; nvram, 512B) completes
successfully (at 15MB/s transfer rates).
none of the processes on the machine are able to do any work, the console is
updated when I hit a key (interrupts are processed), but rc doesn't get a
chance to print a prompt.
the load on the machine before the event wasn't high, but stats showed it
peaking at 8000 just before the machine hung.
things like ^T^Tp work, and in fact I've captured ^T^Tp, ^T^Tq and ^T^Tx if
anyone is interested (^T^Ts doesn't work anymore? it's in the man page).
starting the debugger (^T^TD) caused the machine to hang completely and
irreversibly.
it smells like a race, but my nose isn't that good to be absolutely sure :)
andrey
ps: i've turned dma off now and am runing the same thing again, but dma off
means i'll be able to verify whether the command completed early tomorrow
morning.
^ permalink raw reply [flat|nested] 3+ messages in thread
* [9fans] Re: dd-induced hangs
2003-07-07 22:05 [9fans] dd-induced hangs andrey mirtchovski
@ 2003-07-07 22:18 ` andrey mirtchovski
2003-07-07 22:26 ` [9fans] " David Presotto
1 sibling, 0 replies; 3+ messages in thread
From: andrey mirtchovski @ 2003-07-07 22:18 UTC (permalink / raw)
To: 9fans
the load jumped to 6, not 8 thousand. the reason was that the ready queue at
this time had 6 processes waiting in it -- they piled up immediately after
'the event'...
see, i'm reading it and almost understanding it :) the biggest almost in the
world ;)
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [9fans] dd-induced hangs
2003-07-07 22:05 [9fans] dd-induced hangs andrey mirtchovski
2003-07-07 22:18 ` [9fans] " andrey mirtchovski
@ 2003-07-07 22:26 ` David Presotto
1 sibling, 0 replies; 3+ messages in thread
From: David Presotto @ 2003-07-07 22:26 UTC (permalink / raw)
To: 9fans
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smells like one to me also. We should be able to recreate it.
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From: andrey mirtchovski <mirtchov@cpsc.ucalgary.ca>
To: 9fans@cse.psu.edu
Subject: [9fans] dd-induced hangs
Date: Mon, 7 Jul 2003 16:05:59 -0600 (MDT)
Message-ID: <Pine.LNX.4.44.0307071550240.3842-100000@fbsd.cpsc.ucalgary.ca>
doing 'dd -if /dev/sdC0/arenas -of /dev/sdD0/arenas -bs 8192' hangs the
system with 100% reproducibility (though each occurs after a different
period of time).
the arenas partition is 60GB. running the same command on smaller
partitions (fossil, 13GB; isect, 3GB; 9fat, 10MB; nvram, 512B) completes
successfully (at 15MB/s transfer rates).
none of the processes on the machine are able to do any work, the console is
updated when I hit a key (interrupts are processed), but rc doesn't get a
chance to print a prompt.
the load on the machine before the event wasn't high, but stats showed it
peaking at 8000 just before the machine hung.
things like ^T^Tp work, and in fact I've captured ^T^Tp, ^T^Tq and ^T^Tx if
anyone is interested (^T^Ts doesn't work anymore? it's in the man page).
starting the debugger (^T^TD) caused the machine to hang completely and
irreversibly.
it smells like a race, but my nose isn't that good to be absolutely sure :)
andrey
ps: i've turned dma off now and am runing the same thing again, but dma off
means i'll be able to verify whether the command completed early tomorrow
morning.
^ permalink raw reply [flat|nested] 3+ messages in thread
end of thread, other threads:[~2003-07-07 22:26 UTC | newest]
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2003-07-07 22:05 [9fans] dd-induced hangs andrey mirtchovski
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2003-07-07 22:26 ` [9fans] " David Presotto
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