NTFS safety and lack thereof - Was: Re: Linux 2.4.0ac11

Anton Altaparmakov (aia21@cam.ac.uk)
Wed, 24 Jan 2001 16:54:36 +0000

At 15:05 24/01/01, Cataldo Thomas wrote:
>On Wed, 24 Jan 2001, Alan Cox wrote:
> > 2.4.0-ac11
> > o Major NTFS updates (Anton Altaparmakov)
>Is read access safe ?

Of course read-only is safe. As long as you mount the partition READ-ONLY
nothing can happen to it in any way, your NTFS data is at least safe. It is
possible however that the driver might cause the kernel to crash in the
worst case so you might loose unsaved data on other write mounted
partitions. Note that this is an infrequent event and I have only over
experienced it under extreme load of the driver! Casual use like playing
mp3s from an NTFS partition works fine. On a production system, leaving
NTFS partitions mounted will slowly eat your memory (reported by several
people), mostly it will go into buffers which don't seem to get freed (I
think this is better with more recent kernels but don't have a box with
NTFS partitions which can stay up for more than a day, due to needing to
use windows, to make sure). - There is no detectable memory leak I can see
(I wrote a small memory debugger tracking facility and added it to the
driver and all allocated memory was released when the unmount happened, so
there is no leak, admittedly I need to have this run for longer to make
sure, also none of the memory blocks were overrun in either direction).

To summarize: usage for read only is fine for general, not too heavy duty,
workstation that gets rebooted once every few days, kind of use.

Note that some of the facilities from Windows 2000 NTFS are not available
and the driver will either ignore them or do something stupid, but it will
NOT damage your data.

Write mode is another matter completely! It is extremely DANGEROUS and NOT
suitable for everyday use. I would recommend to never mount an NTFS
partition read/write unless you are a developer and it is either a fully
backed up partition which you can afford to have completely trashed OR your
partition is already trashed / NT/2k isn't working and you are trying to
fix it. Only then is it ok to use it. Also note that the current driver has
no support whatsoever for deleting files/directories. So you can either
create files or copy files on top of others but not delete any of them. And
finally note that dealing with directories is not right so preferably stick
to only creating/copying files without involving the creation of directories.

>I would really be interested by a link to ntfs status in linux. I mean
>what is safe and what is not.

You will have to wait for that kind of thing I am afraid. I might put up
some kind of status page up on sourceforge at some point but not now. More
important things to do. If someone wants to make a web page just drop me a
line and we can put it up on linux-ntfs.sourceforge.net (nothing there at
the moment at all)...

Hope this answers your immediate questions.

Best regards,


    "Programmers never die. They do a GOSUB without RETURN." - Unknown source
Anton Altaparmakov <aia21 at cam.ac.uk> (replace at with @)
Linux NTFS Maintainer / WWW: http://sourceforge.net/projects/linux-ntfs/
ICQ: 8561279 / Home page: http://www-stu.christs.cam.ac.uk/~aia21/

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