[email protected] wrote:
On Mon, 27 Feb 2006 15:41:44 +0100, Anton Altaparmakov
<[email protected]> wrote:
On Mon, 2006-02-27 at 15:27 +0100, Arjan van de Ven wrote:
On Mon, 2006-02-27 at 14:06 +0000, Anton Altaparmakov wrote:
> On Mon, 2006-02-27 at 14:50 +0100, Arjan van de Ven wrote:
> > On Mon, 2006-02-27 at 08:28 -0500, Lennart Sorensen wrote:
> > > On Sun, Feb 26, 2006 at 11:50:40PM +0100,
[email protected] wrote:
> > > > Hi,
> > > >
> > > > OMG what do I have to do to post here? 10th attempt.
> > > > {part2}
> > > >
> > > > Here is a non-exhaustive list of typical devices types
requiring fat vfat
> > > > support:
> > > >
> > > > fd ide-hd scsi-hd usb-hd cdrom usb-hd usb-handheld (iPod,
iRiver etc)
> > > > usb-flash (usbsticks, cameras, some music devices.)
> > > >
> > > > IIRC the sync mount option for vfat is ignored for file
systems >2G, this
> > > > effectively (and probably intentionally) excludes nearly all
hd partitions
> > > > and iPod type devices.
> > >
> > > I think many people wish it was ignored on smaller devices
too given
> > > what it does to write performance.
> >
> > well. If you don't want it *DO NOT USE IT AT THE MOUNT COMMAND
LINE* !!!
>
> That is easy to say when you are using the command line... Modern
> distros (as you know I am sure) mount all hot-plug devices like usb
> keys, usb hard disks, etc automatically at plug-in time and at least
> some distros use "-o sync"
that is a bad misdesign of that distro or at least the tool the distro
uses for this (I don't know which it is so I can say that without
sounding partial :)
the tool that decides to use "sync", or at least the author thereof,
should be aware of what flash is, and that it has a limited lifespan
etc
etc, and that you thus want maximum caching etc.
I agree completely which is why we hack the system to remove the o_sync
on our distro derivative. (-:
But my point was that your solution of "don't do that then" is not much
use to your average user who sits in front of such distro in graphical
desktop as they are not technical enough to find and hack their hotplug
system to work properly...
Best regards,
Anton
If you don't want it *DO NOT USE IT AT THE MOUNT COMMAND LINE* !!!
Yeah, cleaver.
That is not really a constructive responce. I dont use , I do use
command line mount all the time. I never was in danger of damaging my
drive with this new "feature".
Telling a user who has just burnt out a brand new 1GB usb device he
should have RTFM and modified that HAL configuration to insure it did
not use sync it not likely to win much confidence in the linux kernel.
No problem in the kernel. The system is set up wrong. A simple user
may not be able to
figure out his distro's hotplug setup to fix this - but then this problem is
the fault of _the distro_, not the kernel. Complain to distributors
instead.
There is no need for the kernel to treat o_sync VFAT in any special
way. The users,
or more likely the distros, can skip that o_sync part.
Not all distros have such problems either. On debian, I had to set up
/etc/fstab myself -
where not specifying sync is easy enough.
The point of raising this is that the vast majority of linux users
have no awareness of this. If there is a danger of this sync
implementation damaging hardware it should be done differently.
Which is why people is working on the "sync on close" alternative.
More importantly this sync strategy is very likely _increasing_ the
danger of data loss that is the core reason for using sync in the
first place.
To quote from my earlier post:
The new model attempts to be more rigourous by updating the FAT every
time
a block of data is written. Thus the "hammering" of the physical memory
hosting the FAT record.
In view of the nature of flash memory this may actually be drastically
increasing the chance that the whole FAT gets erased.
If a pullout occurs during write , there is now a near 50% chance that
this takes out the entire FAT.
No, only one FAT entry. And the users who pull out during writes
_really_ get
what they deserve anyway. You don't need deep linux knowledge for that.
In the day of the floppy, people respected the activity light regardless
of OS.
Helge Hafting
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