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

Groups > linux.debian.user > #286815

Re: Schrödinger's hash

Show all headers | View raw

On 5/22/26 08:53, 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.
> 
> 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.


On 5/22/26 09:05, Andrew Latham wrote:
 > I had an issue some months back. It turned out to be a bad RAM stick
 > in my NAS. The issues would not show up on a restart but after some
 > usage it would hit the RAM errors and :(


On 5/22/26 09:14, Charles Curley wrote:
 > This is not impossible. I recently had some RAM go bad, failing
 > memtest. I have replaced it with new RAM, which does not fail
 > memtest. Maybe I should let it run for several passes.


When I suspect a memory problem, I run Memtest86+ for 24+ hours:

     https://memtest.org/

     Linux ISO (64 bits) -> mt86plus_8.10_x86_64.iso.zip

The current version sets "CPU Sequencing Mode" to "Parallel (PAR)" by 
default.


I use and suggest ECC memory.


I use and suggest ZFS with redundant disks for storage.


David

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