Michael Osipov <1983-01...@gmx.net> wrote: > Am 2016-10-14 um 11:43 schrieb Fabian Keil: > > Michael Osipov <1983-01...@gmx.net> wrote: > > > >> Am 2016-10-13 um 03:41 schrieb John-Mark Gurney: > >>> Michael Osipov wrote this message on Wed, Oct 12, 2016 at 20:54 > >>> +0200: > >>>> As if there is a bottleneck between socket read and geom write to > >>>> FS. > >>>> > >>>> Is that better? > >>> > >>> Have you run gstat on the system to see if there is an IO bottle > >>> neck? Since you are using graid3, you want to look to see if > >>> it's %busy is ~100, while the underlying components are not. > >> > >> This is hardly impossible because as soon as I start some SFTP > >> transfer, all of my SSH sessions free or receive connetion > >> timeout/abort. Doing a SFTP from FreeBSD to FreeBSD gives me on both > >> physical disks and RAID3 volume a busy of zero to one perfect. In > >> other terms, the drives are bored. > > > > Try checking the FAIL and SLEEP columns in the "vmstat -z" output. > > I assume that you expect a rise on those numbers. I have made several > runs. Rebooted the machine and then started SFTP transfer. After seconds > my SSH sessions locked up. The transfer was aborted manually after 10 > minutes which should have saturated the entire connection. After that, I > reran vmstat -z, no or minimal rise in FAIL and SLEEP.
IIRC the SLEEP column only showns currently sleeping requests, therefore you may want to run "vmstat -z" multiple times while the transfer is ongoing. Having said that, a custom DTrace script would probably be a better tool to diagnose the issue anyway. > Interesting to say that this happens if is is a UFS volume on > gconcat/graid3/gvinum/gstripe configuration. Regular gpart with GPT has > no performance penalty. Additionally, it is not limited to SSH but > virtually everything with sockets: nc, ggate, smb. > > > This could be related to: > > https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=209680#c2 > > It pretty much sounds like it, though I do not use ipfw, pf or any NAT > stuff. I will try your first patch and let you know. > > Do you want me to add my usecase to the issue? If the patch helps, that could be useful once a committer finds the time to look at the PR. Fabian
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