El 2010-05-06 a las 16:36 +0300, Alexander Batischev escribió: (resending to the list)
> Hi, and thanks for response! > > On 6 May 2010 16:17, Camaleón wrote: > >> On my netbook I'm using automatic USB sticks mount through udev rules, > >> and I already used to running 'sync' command before unplugging stick, so > >> no data will be lost. But if I have few sticks inserted and some > >> information copying on one of them, if I run 'sync' I have to wait while > >> copying ends, because: > >> > >> a) sync command drops cache on disk, but copying process fill it again; > >> sync will work until all the caches are dropped to disks > > > > Dunno if this would fit your needs, but there is a "sync" option for > > mount points you can use to ensure all removable devices (or only the > > ones you select) get mounted with "-o sync" flag. > > > > But I would be a bit reluctant to use that, because as per "man mount" > > page that flag can shorten the life of flash drive based devices with a > > limited number of write operations. > > Yes, that's why all USB sticks are mounted with async option and > that's a reason to use 'sync' before unplugging them. O.k. > >> b) I can't unplug stick when it stops to flash because I can't be sure > >> that there are no more parts of cache needed to be flushed on that disk. > >> > >> So here is my question - how can I run sync for only one device? > > > > To avoid data loss you have to "umount" the device first (or just "eject" > > if that options is available in your system). Umount/eject operation > > should care the data is correctly stored in the media before powering off > > or unplugging the device. > > Well, yes, that's right, but I don't unmount sticks by myself — udev > does that when I unplug USB device. Let me describe how automounting > implemented so it would be more clear to you. > > When I put my flash drive into USB port, udev recognizes that, checks > drive for filesystem type, and mount it if it's FAT or NTFS. After > that I can work with mounted stick. Right. > When I unplug stick, udev unmounts it from mountpoint. Pay attention > to moment of unmount - it happens *after* unplugging, so no cache can > be flushed as far as device is already disconnected. > > I though about running umount /mnt/sd[a-z] before unplugging, but then > decided to ask for a better way. If I won't find it, umount will be > the solution. So, any other options? I never do that way. I always first "umount" the device and then, I remove the stick, but not the reverse. Removable media has to be done that way, to prevent data loss or flash drive damage, or that is what manufacturers say :-? Greetings, -- Camaleón -- To UNSUBSCRIBE, email to debian-user-requ...@lists.debian.org with a subject of "unsubscribe". Trouble? Contact listmas...@lists.debian.org Archive: http://lists.debian.org/20100506142143.ga11...@stt008.linux.site
