This comes up quite a bit. It all depends on who how sophisticated you think the person is who may be trying to retrieve the data is.
For 99.99% of the world, just zero'ing the disks (even multiple times if it makes you feel comfortable) is enough.
I suppose you could create some dummy data to put on the disks after you zero out the disks, then zero them out again. But that's a lot of time and effort to get you from 99.99% to 99.999%.
If you are concerned about professional, government-backed efforts to recover the data, then your only real option is to destroy the disks entirely. Bust them into thousands of pieces and dispose of those pieces in different trash containers. While this is certainly expensive since you can't return or re-use the disks, it is by far the most secure. However, there are very few people who need this level of security, but it's an option if your data abosulutely cannot ever be recovered.
Hope this helps.
-- Adam Fox NetApp Professional Services, NC adamfox@netapp.com
-----Original Message----- From: Israel, Meital [mailto:meital.israel@intel.com] Sent: Monday, July 09, 2001 8:55 AM To: NetApp Mailing List (E-mail) Subject: Deleting data on NetApp.
Hi All,
Does anyone know a utility to format the NetApp disks without being able to unformat it?
Thanks,
Meital
I just wish I could delete files on a NetApp from the console. It takes forever and a day to remove a hundred or more GB off a filer from either CIFS or NFS.
An "rm" in the ONTAP CLI would be super handy. It could work *much* faster then over the wire. Further, an "rm -F" to delete files through the active file system and all snapshots would even be keener. =)
-- Jeff
On Mon, Jul 09, 2001 at 07:59:53AM -0700, Fox, Adam wrote:
This comes up quite a bit. It all depends on who how sophisticated you think the person is who may be trying to retrieve the data is.
For 99.99% of the world, just zero'ing the disks (even multiple times if it makes you feel comfortable) is enough.
I suppose you could create some dummy data to put on the disks after you zero out the disks, then zero them out again. But that's a lot of time and effort to get you from 99.99% to 99.999%.
If you are concerned about professional, government-backed efforts to recover the data, then your only real option is to destroy the disks entirely. Bust them into thousands of pieces and dispose of those pieces in different trash containers. While this is certainly expensive since you can't return or re-use the disks, it is by far the most secure. However, there are very few people who need this level of security, but it's an option if your data abosulutely cannot ever be recovered.
Hope this helps.
-- Adam Fox NetApp Professional Services, NC adamfox@netapp.com
-----Original Message----- From: Israel, Meital [mailto:meital.israel@intel.com] Sent: Monday, July 09, 2001 8:55 AM To: NetApp Mailing List (E-mail) Subject: Deleting data on NetApp.
Hi All,
Does anyone know a utility to format the NetApp disks without being able to unformat it?
Thanks,
Meital
If you run multiple rm -r commands in parallel, things get done MUCH faster. Your filer can handle the load no problem and chances are your unix host can easily handle at least 10 rm processes and probably quite a few more, depending on number of processors, etc.
Even on a single CPU unix host, you see dramatic speed up because when one rm process waits for a NFS reply from the server, it relinquishes the CPU to another rm process that is ready to resume running because it's NFS reply has arrived.
Of course, it helps if your data is split up somewhat evenly in several directory trees.
for dir in /some/where/*; do /bin/rm -r $dir & done
I just wish I could delete files on a NetApp from the console. It takes forever and a day to remove a hundred or more GB off a filer from either CIFS or NFS.
Steve Losen scl@virginia.edu phone: 804-924-0640
University of Virginia ITC Unix Support
jkrueger@qualcomm.com (Jeffrey Krueger) writes
I just wish I could delete files on a NetApp from the console. It takes forever and a day to remove a hundred or more GB off a filer from either CIFS or NFS.
Surely it's the number of files, not their size, that matters?
An "rm" in the ONTAP CLI would be super handy.
toaster> priv set advanced Warning: These advanced commands are potentially dangerous; use them only when directed to do so by Network Appliance personnel. toaster*> help rm rm - remove files
Not that I've tried it, with that sort of health warning!
It could work *much* fasterthen over the wire.
The amount of over-the-wire traffic needed to delete zillions of files using NFS isn't really all that large. The delays you see are more likely to be the effect of sub-optimal NFS client implementations. For example, I remember large "rm -r"s to a filer becoming *much* faster after a patch to the NFS client code in Solaris 2.6.
Chris Thompson University of Cambridge Computing Service, Email: cet1@ucs.cam.ac.uk New Museums Site, Cambridge CB2 3QG, Phone: +44 1223 334715 United Kingdom.
i'd like to know the detailed syntax for this. any nice netapp folks just jump in.
Chris Thompson wrote:
jkrueger@qualcomm.com (Jeffrey Krueger) writes
I just wish I could delete files on a NetApp from the console. It takes forever and a day to remove a hundred or more GB off a filer from either CIFS or NFS.
Surely it's the number of files, not their size, that matters?
An "rm" in the ONTAP CLI would be super handy.
toaster> priv set advanced Warning: These advanced commands are potentially dangerous; use them only when directed to do so by Network Appliance personnel. toaster*> help rm rm - remove files
Not that I've tried it, with that sort of health warning!
It could work *much* fasterthen over the wire.
The amount of over-the-wire traffic needed to delete zillions of files using NFS isn't really all that large. The delays you see are more likely to be the effect of sub-optimal NFS client implementations. For example, I remember large "rm -r"s to a filer becoming *much* faster after a patch to the NFS client code in Solaris 2.6.
Chris Thompson University of Cambridge Computing Service, Email: cet1@ucs.cam.ac.uk New Museums Site, Cambridge CB2 3QG, Phone: +44 1223 334715 United Kingdom.
Adam.Fox@netapp.com writes about erasing disc contents:
This comes up quite a bit. It all depends on who how sophisticated you think the person is who may be trying to retrieve the data is.
For 99.99% of the world, just zero'ing the disks (even multiple times if it makes you feel comfortable) is enough.
There remains the question of how to do this conveniently within a NetApp filer. In the past I have made a dummy volume and added the disks to be erased to it, but I wouldn't be too sure that this zeros the area at the end of the disk after the right-sized point.
ONTAP 5.x had a "zero_spares" command in rc_toggle_basic mode, but this seems to have gone from advanced mode in ONTAP 6.x.
I suppose you could create some dummy data to put on the disks after you zero out the disks, then zero them out again. But that's a lot of time and effort to get you from 99.99% to 99.999%.
If you are concerned about professional, government-backed efforts to recover the data, then your only real option is to destroy the disks entirely. Bust them into thousands of pieces and dispose of those pieces in different trash containers.
... and we've had all sorts of imaginative elaborations along the lines of physical mutilation!
I'm no expert on this sort of thing, but wouldn't baking the disc for a few hours at a temperature comfortably above the Curie point of the recording medium be a useful preparatory step?
Chris Thompson University of Cambridge Computing Service, Email: cet1@ucs.cam.ac.uk New Museums Site, Cambridge CB2 3QG, Phone: +44 1223 334715 United Kingdom.
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Chris Thompson -
Fox, Adam -
Jeffrey Krueger -
neil lehrer -
Steve Losen