In situations were BOINC is causing unexpectedly large
(> 1 GB/hour) disk I/O,
we need to figure out the source of the I/O.
-- David

On 17-Jun-2013 11:14 AM, "Steffen Möller" wrote:
Hello,

I presume nobody wants to have the user play too much with any folders. I
liked the "all on a ramdisk" idea, but BOINC occupies more than 10GB on the
machine(s) in question, and it will similarly ask for that much (too much
with today's common 16 or 24 GB setups when adding the memory for the apps)
also for other setups.

The checkpointing interval I understood (asked around) to be ignored by the
client apps of a quite a few projects. Mine is set to some 7200 seconds (two
hours) and the IO does not decrease. It would not be my prime target for
optimisation.

Could it be the graphics? We once observed that SETI without configuration
for graphics is a few %ages faster than the same client with the same
compilation options but graphics-savvy, even though no graphical client was
run. If much IO was used for that, this might be an explanation. I cannot
test this at the moment.

Cheers,

Steffen


Gesendet: Montag, 17. Juni 2013 um 17:20 Uhr Von: "Eric J Korpela"
<[email protected]> An: "Steffen Möller" <[email protected]> Cc:
"[email protected]" <[email protected]> Betreff: Re:
[boinc_dev] Can we do shared memory with no disk usage?

We considered using memory mapped files for the checkpoint state information
in SETI@home, but decided that it was virtually impossible to guarantee
synchronization on exit.  And, of course, the problem with using a ram disk
for checkpoints that the checkpoint data disappears if power is lost.


But if you want checkpoints to not occur, there is a preference for that...
"Tasks checkpoint to disk at most every:   60 seconds"

You can set it to 8 hours.  But you'll also want to choose "suspend to
memory".  Of course the output of the app (which depending on the app might
be more frequent than checkpoints) will still spin up the disks.

If you really want to operate from a ram disk, just copy your project
directory to /dev/shm and link it into /var/lib/boinc/projects.   You'll
still need to back it up occasionally for those times when the power goes
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