Hello, I was asked if it is possible to zero unused space in ext3 partition? Users write to the server via Samba and are far from computer geeks so teaching them to use some safedelete utility is quite impossible. Is there some way or utility to wipe out all the data from unused space? Thanks, Mindaugas
On Thu, 2006-09-07 at 10:25 +0300, Mindaugas wrote:> Hello, > > I was asked if it is possible to zero unused space in ext3 partition? > > Users write to the server via Samba and are far from computer geeks so > teaching them to use some safedelete utility is quite impossible. > > Is there some way or utility to wipe out all the data from unused space? > > Thanks, > > Mindaugas >wow...long time...look read up on like running multi 0S on same box ...like say centos and windows. In order to do that you have to play w/your hard drive space and spec it out... Now I don't remember the command or program you use but I think it's a good start for ya jr -- If ya think you smart,you pretty friggin ignorant. If you think you smart enuf...then you tellin a story, you ready for that challenge!
Mindaugas wrote:> Hello, > > I was asked if it is possible to zero unused space in ext3 partition?Easiest way I can think of is: cat /dev/zero >/fsmountpoint/temp-file Then, after you get the inevitable error that the disk is full: rm /fsmountpoint/temp-file Of course this should probably be done while nobody else is trying to create or enlarge a file, otherwise they could get errors too... -------------- next part -------------- A non-text attachment was scrubbed... Name: signature.asc Type: application/pgp-signature Size: 258 bytes Desc: OpenPGP digital signature URL: <http://listman.redhat.com/archives/ext3-users/attachments/20060907/2c1cf1e0/attachment.sig>
On 9/7/06, Mindaugas <mind at bi.lt> wrote:> > Hello, > > I was asked if it is possible to zero unused space in ext3 partition? > > Users write to the server via Samba and are far from computer geeks so > teaching them to use some safedelete utility is quite impossible. >A safedelete may not work via samba anyway. It doesn't work very well on Windows Native CIFS shares from what my forensics friends have told me.> Is there some way or utility to wipe out all the data from unused space? >For the simplest level of 'wiping' you can try the following: make sure your samba share is its own physical partition seperate from say /var, etc. have a regular job that runs at off hours and does the following: dd if=/dev/zero of=/my/local/filesystem/zero_file when dd dies from lack of space remove /my/local/filesystem/zero_file It wont be DOD regs but it will give some level of cleanliness [where level is better than nothing, but not much.] Your big problem will be that this can/will cause problems with clients that are writing regular data to that disk.> Thanks, > > Mindaugas > > _______________________________________________ > CentOS mailing list > CentOS at centos.org > http://lists.centos.org/mailman/listinfo/centos >-- Stephen J Smoogen. -- CSIRT/Linux System Administrator How far that little candle throws his beams! So shines a good deed in a naughty world. = Shakespeare. "The Merchant of Venice"
> From: Mindaugas [mailto:mind at bi.lt] > Sent: Thursday, September 07, 2006 12:26 AM > To: ext3-users at redhat.com > Cc: CentOS mailing list > Subject: wiping of unused space on ext3 > > > Hello, > > I was asked if it is possible to zero unused space in ext3 > partition? > > Users write to the server via Samba and are far from > computer geeks so teaching them to use some safedelete > utility is quite impossible. > > Is there some way or utility to wipe out all the data from > unused space?I believe you can use the "chattr -s" command to mark all of the files so that when they are deleted, their blocks are wiped with zeros. I believe that you'd need to set up some sort of cron job to make sure all of the files have this attribute set on a regular basis, unless this works as a directory level attribute. ..Chuck..
"Mindaugas" <mind at bi.lt> wrote:> I was asked if it is possible to zero unused space in ext3 partition?I have a couple of patches that add a zerofree mount option to ext2 and ext3 filesystems. The ext2 version is much better tested and more complete: it zeros all file data blocks, directory blocks and extended attributes (though not inode data). The ext3 patch only handles file data, not metadata. I've been meaning to submit these to LKML, but since you ask let's give them an airing here first. Since this is being copied to the CentOS mailing list I should point out that I also have versions of the patches that apply cleanly to the RHEL 4 kernel. I don't have them to hand at the moment but if there's any interest I can provide them later. Some background information and other tools are on my website: http://intgat.tigress.co.uk/rmy/uml/index.html Ron
> "Mindaugas" <mind at bi.lt> wrote: >> I was asked if it is possible to zero unused space in ext3 partition? > > I've been meaning to submit these to LKML, but since you ask let's give > them an airing here first. > > Since this is being copied to the CentOS mailing list I should point > out that I also have versions of the patches that apply cleanly to the > RHEL 4 kernel. I don't have them to hand at the moment but if there's > any interest I can provide them later.Thank you for the answer. Just this request is suspended now so I don't know if I will need those patches anymore. In case I will need them I will ask you for the RHEL4 version. :) Mindaugas
Ron Yorston wrote:> "Mindaugas" <mind at bi.lt> wrote: >> I was asked if it is possible to zero unused space in ext3 partition? > > I have a couple of patches that add a zerofree mount option to ext2 and > ext3 filesystems. The ext2 version is much better tested and more > complete: it zeros all file data blocks, directory blocks and extended > attributes (though not inode data). The ext3 patch only handles file > data, not metadata. > > I've been meaning to submit these to LKML, but since you ask let's give > them an airing here first.Ron, thanks for these patch's - I dont think we can have them included in any official centos-repository hosted kernel, but its good to know that people, should they need this, can get to them here. - K -- Karanbir Singh : http://www.karan.org/ : 2522219 at icq