Groups > comp.os.linux.development.system > #624

Re: shred or scrub

From	David Brown <david.brown@hesbynett.no>
Newsgroups	comp.os.linux.development.system
Subject	Re: shred or scrub
Date	2014-04-18 11:49 +0200
Organization	A noiseless patient Spider
Message-ID	<liqsf7$6sg$1@dont-email.me> (permalink)
References	<limvgj$tse$1@dont-email.me> <slrnlkvkrl.2p2.kristof@vega.codepro.be> <liqmp7$4md$1@dont-email.me>

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On 18/04/14 10:12, crankypuss wrote:
> On 04/17/2014 07:15 AM, Kristof Provost wrote:
>> On 2014-04-16, Bill Cunningham <nospam@nspam.invalid> wrote:
>>>      I am using ext4 on my linux. I'm not quite sure of the
>>> difference in it
>>> and ext3 but anyway; the shred man page says with the ext3 filesystem
>>> shred
>>> cannot be guaranteed to  work.
>>>
>> That's because there's no way to guarantee that the file system will
>> write the new data over the same block as the old data. In fact, in
>> log-structured file systems (like ZFS, but not ext3/4) the file system
>> will deliberately not do this.
>
> That seems very messed up.

Some filesystems work this way for particular reasons, such as wear 
leveling (for SSDs), better distribution of data across the disk or 
disks, minimal head movement (for HDs), minimising overwrites in flash 
(when combined with background garbage collection), less fragmentation 
on some times of access patterns, better re-use of data with 
copy-on-write, better safety on power failures or unexpected breaks 
(such as with USB flash sticks), cheap snapshots and rollbacks, etc.

There are many different strategies for how to put data onto disks - no 
one size fits all usage.

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Thread

shred or scrub "Bill Cunningham" <nospam@nspam.invalid> - 2014-04-16 18:17 -0400
  Re: shred or scrub crankypuss <crankypuss@nomail.invalid> - 2014-04-17 04:19 -0600
    Re: shred or scrub "Bill Cunningham" <nospam@nspam.invalid> - 2014-04-18 22:30 -0400
      Re: shred or scrub Jasen Betts <jasen@xnet.co.nz> - 2014-04-19 07:42 +0000
        Re: shred or scrub Richard Kettlewell <rjk@greenend.org.uk> - 2014-04-19 10:04 +0100
      Re: shred or scrub crankypuss <crankypuss@nomail.invalid> - 2014-04-19 02:15 -0600
      Re: shred or scrub Rainer Weikusat <rweikusat@mobileactivedefense.com> - 2014-04-19 23:05 +0100
        Re: shred or scrub crankypuss <crankypuss@nomail.invalid> - 2014-04-20 02:47 -0600
          Re: shred or scrub John Hasler <jhasler@newsguy.com> - 2014-04-20 07:56 -0500
            Re: shred or scrub crankypuss <crankypuss@nomail.invalid> - 2014-04-21 03:51 -0600
              Re: shred or scrub Jasen Betts <jasen@xnet.co.nz> - 2014-04-21 11:50 +0000
                Re: shred or scrub crankypuss <crankypuss@nomail.invalid> - 2014-04-21 06:14 -0600
            Re: shred or scrub "Bill Cunningham" <nospam@nspam.invalid> - 2014-04-21 18:44 -0400
          Re: shred or scrub Rainer Weikusat <rweikusat@mobileactivedefense.com> - 2014-04-21 13:24 +0100
            Re: shred or scrub crankypuss <crankypuss@nomail.invalid> - 2014-04-22 04:10 -0600
              Re: shred or scrub Rainer Weikusat <rweikusat@mobileactivedefense.com> - 2014-04-22 14:39 +0100
  Re: shred or scrub Kristof Provost <kristof@codepro.be> - 2014-04-17 13:15 +0000
    Re: shred or scrub John Hasler <jhasler@newsguy.com> - 2014-04-17 09:40 -0500
      Re: shred or scrub Kristof Provost <kristof@codepro.be> - 2014-04-18 14:40 +0000
    Re: shred or scrub crankypuss <crankypuss@nomail.invalid> - 2014-04-18 02:12 -0600
      Re: shred or scrub David Brown <david.brown@hesbynett.no> - 2014-04-18 11:49 +0200
        Re: shred or scrub crankypuss <crankypuss@nomail.invalid> - 2014-04-18 09:59 -0600
          Re: shred or scrub David Brown <david.brown@hesbynett.no> - 2014-04-21 16:14 +0200
            Re: shred or scrub crankypuss <crankypuss@nomail.invalid> - 2014-04-22 04:22 -0600
              Re: shred or scrub David Brown <david.brown@hesbynett.no> - 2014-04-23 00:06 +0200
                Re: shred or scrub crankypuss <crankypuss@nomail.invalid> - 2014-04-23 05:50 -0600
                Re: shred or scrub David Brown <david.brown@hesbynett.no> - 2014-04-24 22:46 +0200
                Re: shred or scrub crankypuss <crankypuss@nomail.invalid> - 2014-04-25 03:57 -0600
                Re: shred or scrub Rainer Weikusat <rweikusat@mobileactivedefense.com> - 2014-04-25 19:14 +0100
                Re: shred or scrub crankypuss <crankypuss@nomail.invalid> - 2014-04-26 04:02 -0600
                Re: shred or scrub Rainer Weikusat <rweikusat@mobileactivedefense.com> - 2014-04-27 21:26 +0100
                Re: shred or scrub crankypuss <crankypuss@nomail.invalid> - 2014-04-28 03:27 -0600
                Re: shred or scrub Rainer Weikusat <rweikusat@mobileactivedefense.com> - 2014-04-28 12:17 +0100
                Re: shred or scrub Rainer Weikusat <rweikusat@mobileactivedefense.com> - 2014-04-28 13:01 +0100
                Re: shred or scrub crankypuss <crankypuss@nomail.invalid> - 2014-04-29 02:50 -0600
                UNIX(*)/ Linux history & system design (was: shred or scrub) Rainer Weikusat <rweikusat@mobileactivedefense.com> - 2014-05-05 21:31 +0100
                Re: UNIX(*)/ Linux history & system design crankypuss <crankypuss@nomail.invalid> - 2014-05-05 16:02 -0600
                Re: UNIX(*)/ Linux history & system design David Brown <david.brown@hesbynett.no> - 2014-05-06 01:17 +0200
                Re: UNIX(*)/ Linux history & system design crankypuss <crankypuss@nomail.invalid> - 2014-05-06 01:46 -0600
                Re: UNIX(*)/ Linux history & system design Rainer Weikusat <rweikusat@mobileactivedefense.com> - 2014-05-06 15:09 +0100
                Re: UNIX(*)/ Linux history & system design crankypuss <crankypuss@nomail.invalid> - 2014-05-06 23:47 -0600
                Re: UNIX(*)/ Linux history & system design Rainer Weikusat <rweikusat@mobileactivedefense.com> - 2014-05-07 16:23 +0100
                Re: UNIX(*)/ Linux history & system design crankypuss <crankypuss@nomail.invalid> - 2014-05-07 10:51 -0600
                Re: UNIX(*)/ Linux history & system design Jerry Peters <jerry@example.invalid> - 2014-05-07 20:25 +0000
                Re: UNIX(*)/ Linux history & system design crankypuss <crankypuss@nomail.invalid> - 2014-05-08 03:50 -0600
                Re: UNIX(*)/ Linux history & system design Jerry Peters <jerry@example.invalid> - 2014-05-08 20:24 +0000
                Re: UNIX(*)/ Linux history & system design crankypuss <crankypuss@nomail.invalid> - 2014-05-09 02:23 -0600
                Re: UNIX(*)/ Linux history & system design Rainer Weikusat <rweikusat@mobileactivedefense.com> - 2014-05-09 18:36 +0100
                Re: UNIX(*)/ Linux history & system design Rainer Weikusat <rweikusat@mobileactivedefense.com> - 2014-05-09 21:24 +0100
                Re: UNIX(*)/ Linux history & system design Rainer Weikusat <rweikusat@mobileactivedefense.com> - 2014-05-07 22:01 +0100
                Re: UNIX(*)/ Linux history & system design crankypuss <crankypuss@nomail.invalid> - 2014-05-08 03:37 -0600
                Re: UNIX(*)/ Linux history & system design Rainer Weikusat <rweikusat@mobileactivedefense.com> - 2014-05-08 14:02 +0100
                Re: UNIX(*)/ Linux history & system design crankypuss <crankypuss@nomail.invalid> - 2014-05-09 02:56 -0600
                Re: UNIX(*)/ Linux history & system design David Brown <david.brown@hesbynett.no> - 2014-05-07 00:15 +0200
                Re: UNIX(*)/ Linux history & system design crankypuss <crankypuss@nomail.invalid> - 2014-05-07 00:32 -0600
                Re: UNIX(*)/ Linux history & system design Jorgen Grahn <grahn+nntp@snipabacken.se> - 2014-05-07 08:47 +0000
                Re: UNIX(*)/ Linux history & system design crankypuss <crankypuss@nomail.invalid> - 2014-05-07 10:59 -0600
                Re: UNIX(*)/ Linux history & system design Rainer Weikusat <rweikusat@mobileactivedefense.com> - 2014-05-06 14:35 +0100
                Re: shred or scrub David Brown <david.brown@hesbynett.no> - 2014-04-26 16:30 +0200
                Re: shred or scrub crankypuss <crankypuss@nomail.invalid> - 2014-04-27 05:59 -0600
                Re: shred or scrub Rainer Weikusat <rweikusat@mobileactivedefense.com> - 2014-04-27 20:15 +0100
                Re: shred or scrub crankypuss <crankypuss@nomail.invalid> - 2014-04-28 03:29 -0600
                Re: shred or scrub Rainer Weikusat <rweikusat@mobileactivedefense.com> - 2014-04-28 12:06 +0100
                Re: shred or scrub David Brown <david.brown@hesbynett.no> - 2014-04-27 21:41 +0200
                Re: shred or scrub crankypuss <crankypuss@nomail.invalid> - 2014-04-28 04:03 -0600
                Re: shred or scrub Richard Kettlewell <rjk@greenend.org.uk> - 2014-04-28 16:44 +0100
                Re: shred or scrub David Brown <david.brown@hesbynett.no> - 2014-04-28 23:39 +0200
      Re: shred or scrub John Hasler <jhasler@newsguy.com> - 2014-04-18 07:37 -0500
        Re: shred or scrub crankypuss <crankypuss@nomail.invalid> - 2014-04-18 10:16 -0600
          Re: shred or scrub John Hasler <jhasler@newsguy.com> - 2014-04-18 12:01 -0500
      Re: shred or scrub Kristof Provost <kristof@codepro.be> - 2014-04-18 14:42 +0000
  Re: shred or scrub David Brown <david.brown@hesbynett.no> - 2014-04-17 16:41 +0200

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