Am 2016-10-14 um 11:43 schrieb Fabian Keil:
Michael Osipov <> 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
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

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.

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:

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?


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