Re: USB-Storage, slow speed with sync option

[Erik Slagter <erik@slagter.name>]

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On Wed, 2005-09-14 at 14:45 +0200, Lionel Bouton wrote:
> >>Why would you _ever_ want to use the sync mount option on a flash
> >>device?
> >Don't ask me:-)

> >I used to mount without sync option, but I switched to hal + dbus now
> >and with gentoo it automatically sets sync option in fstab :-(

> This is purely a PBKAK :
> users want to remove the device as soon as they get feedback from their 
> UI telling them that their transfer is done (in fact they even screw up 
> and remove the device before it is done). sync in fstab isn't 
> particularly clever, but sync with automount is more useful : when 
> properly configured, as soon as the transfer is done the automounter can 
> cleanly umount the block device which is nearly instantaneous when sync 
> is used. Without sync there can be some awfully long delays with flash 
> and huge caches (on a 512M slow SD, I saw 30+ seconds after transfering 
> 10s or 100s of MB).

> This is understandable, for all the removable devices without a clean 
> "eject" and VFAT formatted, using sync is probably the best safeguard 
> against badly screwed up filesystems.

It's a very bad solution, because it's slow, but worse, it wears out
particular sectors, although the only good option (make the stick
non-removable when in use is not quite feasible).

People must be instructed to eject() before plug out. Just like
floppies.

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