http://brainstorm.ubuntu.com/item/8083/ #8033 and #7989 with some improvements.

Problems with USB Flash Unmounting: 1) When you pull the plug on a drive, the system does not detect it and take care of the forced unmount for you. User has to go to command line. 2) When you unplug a drive, even when the light isn't blinking, unflushed buffers can cause significant data loss for no apparent reason.

Solution:

1) the system should detect when the drive is unplugged and if it is still mounted, a forced unmount should occur. This will prevent the user from having to use the command line for an every day occurrence. Many newbies reboot the system to get rid of this error state.

2) There should be a timeout set that after X seconds of inactivity (I propose 5 seconds) the write buffer should be flushed.

3) A new .fslog (or similar) file should be installed in all usb flash drives upon connection. If its a journaled filesystem, then don't, but for fat32 and others, it should do this. It will have the following function:
a. for every flush of the write buffer due to the timeout in part (2), write an entry into the log at the end indicating all writes are complete. This can be called the "clean" state
b. when writing to the disk with an initially empty write buffer, check to see if the log indicates a clean or dirty state. If clean, change the state to dirty.
c. when mounting a flash drive the system should read the log file, detect whether it is dirty or clean, and do a fsck if dirty, warning the user to not unplug the drive when it is in use.
d. Due to (a) and (b), at maximum, a log write could only occur once after 5 seconds of inactivity if the buffer has data in it. So it would not reduce lifespan of the flash. And even if your worried about flushing after 5 seconds, it would only correspond to writes already on their way to the disk, negating any problem with limited writes and lifespan of the drive.

The log file will be of negligible size and only grow with one entry for file transfers that happen greater than 5 seconds apart. Lifespan of the drive will not be hurt because these log entries will be VERY small and will only happen when writing activity is already going to happen to the disk anyway. The log can be cleaned up upon mounting of the drive. Since there is already a daemon running in the background to auto mount a USB flash drive, this functionality should be added to said daemon.





[175 votes] Solution #1: Auto-generated solution of idea #8083


[2 votes] Solution #2: Low-level device read/write suspend/resume, Visual feedback when device in use


]]> en-us Mon, 05 May 2008 02:16:35 +0000 Sun, 08 Jun 2008 08:09:10 +0000 QAPoll module http://brainstorm.ubuntu.com/idea/8083/
Thanks.]]> Mon, 05 May 2008 15:17:45 +0000
I think that, at least, users ought to be able to select "sync" as the default for hot-plugged storage devices from somewhere in the systemsettings GUI(s). At the moment, I don't think it's even possible without editing some magic hot-plug script somewhere.

The obvious problem is that if you use a USB interface for disks you don't expect to remove often (e.g. a Drobo), it would slow down all processes doing I/O to them.]]> Mon, 05 May 2008 18:05:56 +0000 Tue, 06 May 2008 00:27:59 +0000 I'll vote this down like the others:"please kill my flash memory as fast as posible ideas".

because according to me disk buffers should stay for 2-5 minutes and it's too long to prevent "surprise" umounts.

And I'd rather learn to properly umount drives than loose drives frequently (with their files of course)]]> Tue, 06 May 2008 13:56:24 +0000
ALSO... Is it known which devices have lower (re)write lifetimes? Perhaps behavior in the background with regard to flush timeouts or use of sync/write-thru (whatever) can be decided intelligently by examining the device IDs.

Mojo
]]> Wed, 07 May 2008 13:53:35 +0000
The whole purpose of the write buffer is so applications don't have to wait on disk I/O to work properly. So they get instant write access to RAM and the GUI is snappy for the user.

Are you telling me that you would sit around modifying the same file multiple times, and saving it every so often, and you would prefer that it NOT be written to the disk?

Your perception of reality is just plain backwards.]]> Thu, 08 May 2008 02:24:14 +0000

1) Be able to mark them as fully synced, or not synced FROM A GUI!!!
2) Allow users to be able to change if they are synced or unsynced. Apple does this with the ipods.
3) Also track all transactions in ram, and if the drive is pulled out whilst there are still some, tell the user to plug it back in or they will lose data. Then they plug it in, it finishes the transactions, and then automatically eject it and tell the user when done.
4) I dont agree flushing every 5 seconds, I find it better to perform the same as it is now, but when idle, flush. In heavy I/O situations, you don't want to also be flushing your USB drive. ]]> Thu, 08 May 2008 03:42:15 +0000 Thu, 08 May 2008 07:57:34 +0000 Thu, 08 May 2008 23:06:05 +0000 Fri, 09 May 2008 09:56:32 +0000 Thu, 15 May 2008 03:10:52 +0000
That is, before he made his own custom script to guide him through the process of remounting the drive at the proper place.]]> Sun, 08 Jun 2008 08:09:10 +0000