Re: logging writes to disk (keeping disk from spinning down)

[Stefan Monnier <monnier@iro.umontreal.ca>]

> You can abuse laptop mode and do
> echo 1 > /proc/sys/vm/block_dump
> and then look in the syslog I think.

It's no abuse at all: it's the just The Right Way to do it.
BEWARE, tho: make sure your syslog doesn't get written to disk,
otherwise you'll get a storm of writes causing other writes ad-nauseum.

Personally I do it this way:
1 - turn off your usual syslog daemon (e.g. /etc/init.s/rsyslogd stop)
2 - turn on a RAM-only syslog daemon, e.g.:

     busybox syslogd -C16
     busybox klogd

then use "busybox logread" or "busybox logread -f" to look at
the syslog.

> You may need to also enable laptop mode
> for this to work (at least used to be the case)
> echo 1 > /proc/sys/vm/laptop_mode

No, block_dump is not tied to laptop-mode, so it can be
used independently.


        Stefan