Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]

Groups > linux.debian.user > #286816

Re: Schrödinger's hash

Show all headers | View raw

[Multipart message — attachments visible in raw view] - view raw

On Fri, 2026-05-22 at 09:53 -0600, Charles Curley wrote:
> I have four four terabyte hard drives. Each has a partition on it.
> The
> four partitions comprise a RAID 5 array using mdadm. On top of that,
> LUKS encryption, then LVM with ext4 logical volumes.

I remarked to a local computer repair shop that I have a four TB backup
drive. He said "replace it. Four TB isn't ready yet."

> On one LVM partition I have a number of backup files, tarred,
> bzipped, and sha256 and sha512 summed. I have a script which will
> find
> checksum files, and execute the appropriate program to test the
> archives. It puts each program into the background, parallising any
> number of checksum tests.
> 
> Starting about a week ago, the script finds an error in one or more
> files out of several. Results are inconsistent: one pass may find an
> error in a given file, the next pass not find any errors in it.
> Running
> checksums manually, one at a time, does not turn up an error. Running
> "tar tvf" finds no error in a suspect file. Running "bunzip2 -t" also
> turns up no error. Only running the script turns up any errors.
> 
> I create two checksum files when I create the backups, for sha256 and
> sha512. After this problem surfaced (about a week ago), I then made
> two
> new checksum files of a suspect file. The two checksum file pairs
> (e.g. both sha512sum files) show the same checksums. The script now
> tests using both the old and new checksum files. Sometime only one
> pair
> of checksum files fail the suspect file.
> 
> In addition to all of that, I also get the occasional "bad message"
> error. I have no idea what that means, but an fsck seems to deal with
> it.
> 
> To be thorough, I have run extended SMART tests on the hard drives,
> kicked mdadm into testing the RAID array, and fscked the LVM
> partitions
> on the RAID array. Only fsck turned up issues, and that has not
> stopped.
> 
> I also back some of this up to offsite USB drives. I ran the script
> on
> one of those, using a different computer. No errors reported.
> 
> I have a hypothesis as to what is going on, but would like to hear
> from
> you before I discuss it.
> 

Back to linux.debian.user | Previous | Next — Previous in thread | Next in thread | Find similar

Thread

Schrödinger's hash Charles Curley <charlescurley@charlescurley.com> - 2026-05-22 18:00 +0200
  Re: Schrödinger's hash Andrew Latham <lathama@gmail.com> - 2026-05-22 18:10 +0200
    Re: Schrödinger's hash Charles Curley <charlescurley@charlescurley.com> - 2026-05-22 18:20 +0200
      Re: Schrödinger's hash Andrew Latham <lathama@gmail.com> - 2026-05-22 18:30 +0200
        Re: Schrödinger's hash Charles Curley <charlescurley@charlescurley.com> - 2026-05-22 19:00 +0200
    bad RAM (Was: Schrödinger's hash) nwe <nwe@gitcoding.net> - 2026-05-22 19:40 +0200
      Re: bad RAM (Was: Schrödinger's hash) Charles Curley <charlescurley@charlescurley.com> - 2026-05-22 22:10 +0200
        Re: bad RAM (Was: Schrödinger's hash) nwe <nwe@gitcoding.net> - 2026-05-22 22:30 +0200
          Re: bad RAM (Was: Schrödinger's hash) Charles Curley <charlescurley@charlescurley.com> - 2026-05-22 23:10 +0200
            Re: bad RAM (Was: Schrödinger's hash) nwe <nwe@gitcoding.net> - 2026-05-22 23:30 +0200
          Re: bad RAM (Was: Schrödinger's hash) David Christensen <dpchrist@holgerdanske.com> - 2026-05-23 02:00 +0200
  Re: Schrödinger's hash The Wanderer <wanderer@fastmail.fm> - 2026-05-22 18:20 +0200
    Re: Schrödinger's hash Charles Curley <charlescurley@charlescurley.com> - 2026-05-22 19:10 +0200
  Re: Schrödinger's hash David Christensen <dpchrist@holgerdanske.com> - 2026-05-22 20:10 +0200
  Re: Schrödinger's hash Van Snyder <van.snyder@sbcglobal.net> - 2026-05-22 20:40 +0200
    Re: Schrödinger's hash nwe <nwe@gitcoding.net> - 2026-05-22 21:50 +0200
      Re: Schrödinger's hash David Christensen <dpchrist@holgerdanske.com> - 2026-05-23 01:30 +0200
        Re: Schrödinger's hash Van Snyder <van.snyder@sbcglobal.net> - 2026-05-23 01:40 +0200
        Re: Schrödinger's hash nwe <nwe@gitcoding.net> - 2026-05-23 02:20 +0200
          Re: Schrödinger's hash David Christensen <dpchrist@holgerdanske.com> - 2026-05-23 07:50 +0200
            Home server (Was: Re: Schrödinger's hash) nwe <nwe@gitcoding.net> - 2026-05-23 17:00 +0200
              Re: Home server (Was: Re: Schrödinger's hash) David Christensen <dpchrist@holgerdanske.com> - 2026-05-24 04:30 +0200

csiph-web