[ubuntu-uk] ubuntu-uk Digest, Vol 17, Issue 2

Chris Jones cmsj at canonical.com
Wed Sep 6 09:41:00 BST 2006


Hi

On Tue, 2006-09-05 at 21:46 +0100, Ted Smith (F3 Web Site Administrator)
wrote:
> The delays in writes are due to the fact that Ubuntu uses journaling
> file systems

The previous poster specifically mentioned VFAT, which afaik is not in
any way journalled. OS write caches and journalling are two separate
things.

Whenever you use a removable device, you should always take care to
correctly unmount it before you remove the device. dragging the files
and then ripping the device out as soon as nautilus's progress bar
finishes is pretty much guaranteed not to have written your data to the
device, or worse, may have written part of it, or even worse, partly
updated the fs metadata (a very very bad time to remove the device as
you can easily hose the whole fs).
When you right click on a removable device in Dapper and tell it to
unmount/eject, you get another progress window that shows the actual
writing (and if you have a removable device with an LED on it that shows
accesses, you'll notice that this is when it does most of its blinking).

If you're super paranoid, some judicious calls to "sync" will ensure
that outstanding write caches are flushed to disk before you remove the
device, but this is basically what the dapper unmount progress window is
doing, afaics.

Cheers,
-- 
Chris Jones
  cmsj at canonical.com
   www.canonical.com




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