Thank you very much :)
* Mikael Liljeroth <firstname.lastname@example.org> wrote:Yes, if you have more than adequate RAM on that machine, it is possible,
> Thanks for the answer.
> I'm sorry I should have been more precise. In my case the files are more
> than a couple of days old and they are not the last modified on the system,
> is this still the desired behaviour?
that the pages were not flushed to disk, before some outage :(
You can flush all current fs cache via sync(8). Also most RAM of the
page cache can be flushed on linux also. Here is a goot drescription of
This is very difficult to analyse. It may be restoreable via the
> Do you mean that the order and time the log records are written to disk
> could not be the reason why my files have been truncated? Just out of
> curiousity, where can I find information on what exactly the order and
> timing of log records disk writes depend on? I read in this (
difference of the pmap and wmap tables of the dmap structure,
which is a part of the allocation bitmap.
I have a tool, which can dump the content of the two bitmaps, so you can
get the difference of the two. And of cause, there may be some data
which was partly written.
crate a cronjob, which does a sync:
> I do not need a ponies flag, just something to improve the situation a
> little. I would be willing to accept that files were truncated, but not
> files that are more than a couple of hours old. The best solution for me
> would be something without having to modify the source of my own
> applications if possible. Patching the kernel or jfsutils or modifying some
> parameter would be better for my particular situation.
> Regarding the fsync approach, would it be possible to do this system wide
> or does it have to be the process holding the filedescriptor to that
> particular file? I'm thinking something like a separate process with a
> timer that issues a fsync every 10 min or so?
# mkdir /etc/cron.minute
# echo '*/1 * * * * /usr/sbin/run-cron /etc/cron.minute' \
> /var/spool/cron/root (or: cronatb -e)
# echo sync > /etc/cron.minute/do-a-sync
# chmod +x /etc/cron.minute/do-a-sync
The prog is available here, but only pmap is dumped, you have to modify
it a bit: http://www.mcmilk.de/projects/frisbee-ng/dl/ ...
If you need help with the bitmap dump tool (fng-info), just send another
mail to this list.
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