SLUG Mailing List Archives
Re: [SLUG] Hotplug and cached Disk writes
- To: steve@xxxxxxxxxxxxx
- Subject: Re: [SLUG] Hotplug and cached Disk writes
- From: Dean Hamstead <djzort@xxxxxxxxxxx>
- Date: Tue Sep 25 13:35:01 2001
- Cc: slug@xxxxxxxxxxx
Is there a setting to change the amount of cache?
of cache per filesystem? even the life of a cache
before it syncs?
all of which set to zero or another minimalistic
value would serve to push data to the fs on the fly
Steve Downing wrote:
> >From the wouldn't it be cool if.... Department:
> Is it possible to tell the kernel NOT to cache disk writes to a certain
> mounted filesystem. Then if that mount suddenly dissappears, everything
> has been already written.
> 1. Using hotplug I plug in a small USB key flash-memory filesystem.
> 2. Hotplug then insert the right kernel modules and mounts the flash-
> memory filesystem in the desired spot.
> 3. Copy/delete/move files onto or off the flash-memory. (NOTE: It
> all works up to here.)
> 4. Pause to allow files to be written WITHOUT kernel caching the write.
> 5. Unceremoniously Pull out the USB key. Hotplug realises and unmounts
> filesystem and rmmods the unused modules.
> Step 5 is the killer. I'm not sure it's even sane without risking
> the obvious possible disk corruption.
> a) I'm not sure hotplug can do the unmounting, it doesn't seem to
> have a pre/post-removal thing.
> b) Win98 doesn't seem handle it properly, so why should I expect
> Linux to.
> FWIW Kernel 2.4.3, Hotplug 0.0.20010919 out of Debian unstable, Modutils
> Is anyone else trying something like this?
> The most exciting phrase to hear in science,
> the one that heralds new discoveries, is not
> "Eureka!" but "That's funny..."' - Isaac Asimov
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