On Thu, 26 Aug 2021 10:48:15 -0700 Gordon Messmer <gordon.mess...@gmail.com> wrote:
> On 8/25/21 9:26 PM, Samuel Sieb wrote: > > You could add a "sync" after the copy and before the "umount". > > > https://utcc.utoronto.ca/~cks/space/blog/unix/TheLegendOfSync > > We're getting into myths and legends territory. Running sync before > umount isn't harmful, but umount will flush any dirty buffers, so it > isn't necessary. > > I'm not able to reproduce the problem described, though I'm running > Fedora 34. When I attach a USB drive, it is mounted with the "flush" > option. I can copy arbitrarily large file sets to the drive, and the > "cp" command appears to be nearly synchronous. The sequence "time cp > ... ; time umount ..." indicates nearly all of the time spent is in > the cp command and umount requires between .2 and .3 seconds. > > What are the indications that the copy operation originally reported > was incomplete? Does the "umount" command have any flags? Are there > any errors in "dmesg" after the script runs? I was not aware of the mount flush option. Just what was needed. Thanks. The MP3 files that were being transferred were empty. The problem emerged only recently on a Fedora 32 system that is untouched since end-of-life, so its not entirely surprising that its not reproducible, let alone on 34. dmesg says FAT-fs (sdb1): Volume was not properly unmounted. Some data may be corrupt. Please run fsck. That says it all. Pity I never looked. Again, thanks. _______________________________________________ users mailing list -- users@lists.fedoraproject.org To unsubscribe send an email to users-le...@lists.fedoraproject.org Fedora Code of Conduct: https://docs.fedoraproject.org/en-US/project/code-of-conduct/ List Guidelines: https://fedoraproject.org/wiki/Mailing_list_guidelines List Archives: https://lists.fedoraproject.org/archives/list/users@lists.fedoraproject.org Do not reply to spam on the list, report it: https://pagure.io/fedora-infrastructure
