So here is why sync sucks only on a usb 2.0 connection. The host fills up the disks write cache some portion of (32MB/64MB/128MB) and then the disk waits for the head get to were the data needs to be written and writes it, as the write cache clears space the host sends more data, but at usb2.0 the host cannot send data as fast as the disk is writing so cannot keep up and the write cache will empty. Once the head is no longer writting (location has passed under the head) then the disk write cache will fill and the disk needs to wait for the head to come back around (probably around 10ms) and then this happens again.
At 6000 rpm that is about 100 writes / second and given a 2mb/sec rate then the write cache being used is around 20MB. At 3.0 speeds the usb bus is fast enough that the write cache should not empty very often and so it is rare that the disk is waiting for the disk head to be at the right location to write the data. On Fri, Aug 16, 2024 at 8:34 AM Andre Robatino <robat...@fedoraproject.org> wrote: > > Installing the nemo Bodhi update from > https://bodhi.fedoraproject.org/updates/FEDORA-2024-4717e54d2b does cause > sync to be eliminated from the line in /proc/mounts, and my transfer speed is > back to normal. Thanks for the replies! > -- > _______________________________________________ > 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, report it: > https://pagure.io/fedora-infrastructure/new_issue -- _______________________________________________ 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, report it: https://pagure.io/fedora-infrastructure/new_issue
