Hello Charles, On Tue, Jun 30, 2026 at 02:47:26PM -0600, Charles Curley wrote: > I have four four terabyte hard drives. Each has one 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 early in May, the script found 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 tarball. 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, 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. SMART showed > problems with one hard drive. I replaced the drive. That did not solve this > problem. However, while the drive was "failed" and before the replacement > installed, the error count went down noticeably. > > I also back some of this up to offsite USB drives. I ran the script on one of > those, using this computer, and a different computer. No errors reported. > > I believe a successful work-around is to install the backports kernel, > linux-image-7.0.10+deb13-amd64 et seq. This problem went away, although > another similar problem has occurred with that kernel. > > There is extensive discussion of this problem on the Debian user list, under > the subject "Schrödinger's hash", starting at > https://lists.debian.org/debian-user/2026/05/msg00377.html
You got a reply to your report, but you might not have noticed it unless you subscribed to the bug. So in case you missed it: Tj suggested to run memtest86+ on your system to rule out (or confirm) RAM issues. You don't happen to have overclocked your system? Best regards Uwe
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