[Beowulf] Data Destruction

[Skylar Thompson]

In this case, we've successfully pushed back with the granting agency (US NIH,
generally, for us) that it's just not feasible to guarantee that the data
are truly gone on a production parallel filesystem. The data are encrypted
at rest (including offsite backups), which has been sufficient for our
purposes. We'll then just use something like GNU shred(1) to do a
best-effort secure delete.

In addition to RAID, other confounding factors to be aware of are snapshots
and cached data.

On Wed, Sep 29, 2021 at 10:52:33AM -0400, Paul Edmon via Beowulf wrote:
> I guess the question is for a parallel filesystem how do you make sure you
> have 0'd out the file with out borking the whole filesystem since you are
> spread over a RAID set and could be spread over multiple hosts.
> 
> -Paul Edmon-
> 
> On 9/29/2021 10:32 AM, Scott Atchley wrote:
> > For our users that have sensitive data, we keep it encrypted at rest and
> > in movement.
> > 
> > For HDD-based systems, you can perform a secure erase per NIST
> > standards. For SSD-based systems, the extra writes from the secure erase
> > will contribute to the wear on the drives and possibly their eventually
> > wearing out. Most SSDs provide an option to mark blocks as zero without
> > having to write the zeroes. I do not think that it is exposed up to the
> > PFS layer (Lustre, GPFS, Ceph, NFS) and is only available at the ext4 or
> > XFS layer.
> > 
> > On Wed, Sep 29, 2021 at 10:15 AM Paul Edmon <pedmon at cfa.harvard.edu
> > <mailto:pedmon at cfa.harvard.edu>> wrote:
> > 
> >     The former.  We are curious how to selectively delete data from a
> >     parallel filesystem.  For example we commonly use Lustre, ceph,
> >     and Isilon in our environment.  That said if other types allow for
> >     easier destruction of selective data we would be interested in
> >     hearing about it.
> > 
> >     -Paul Edmon-
> > 
> >     On 9/29/2021 10:06 AM, Scott Atchley wrote:
> > >     Are you asking about selectively deleting data from a parallel
> > >     file system (PFS) or destroying drives after removal from the
> > >     system either due to failure or system decommissioning?
> > > 
> > >     For the latter, DOE does not allow us to send any non-volatile
> > >     media offsite once it has had user data on it. When we are done
> > >     with drives, we have a very big shredder.
> > > 
> > >     On Wed, Sep 29, 2021 at 9:59 AM Paul Edmon via Beowulf
> > >     <beowulf at beowulf.org <mailto:beowulf at beowulf.org>> wrote:
> > > 
> > >         Occassionally we get DUA (Data Use Agreement) requests for
> > >         sensitive
> > >         data that require data destruction (e.g. NIST 800-88). We've
> > >         been
> > >         struggling with how to handle this in an era of distributed
> > >         filesystems
> > >         and disks.  We were curious how other people handle requests
> > >         like this?
> > >         What types of filesystems to people generally use for this
> > >         and how do
> > >         people ensure destruction?  Do these types of DUA's preclude
> > >         certain
> > >         storage technologies from consideration or are there creative
> > >         ways to
> > >         comply using more common scalable filesystems?
> > > 
> > >         Thanks in advance for the info.
> > > 
> > >         -Paul Edmon-
> > > 
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-- 
Skylar