Date: Sat, 15 Oct 2016 14:01:59 +0200 From: Michael Osipov <mosipov@gmx.de> To: freebsd-geom@freebsd.org Subject: Re: Abysmally slow write to geom class volume over network Message-ID: <90ca3d9c-6016-8a63-64c5-ce3f829756dd@gmx.de> In-Reply-To: <20161015132249.607b374c@fabiankeil.de> References: <33da0f73-48f1-4727-fe76-41343dc4955b@gmx.net> <18314f27-849b-31df-d88d-af64e89c133f@gmx.net> <346c7da7-02b2-ba34-1463-f3f0a5a3cd9a@rlwinm.de> <15e9cb94-7ad8-e547-b06a-699ce2250624@gmx.net> <20161013014143.GA1669@funkthat.com> <636763f0-a732-18ba-262b-c3fc01f4342c@gmx.net> <20161014114330.396fe534@fabiankeil.de> <5a12f70d-3488-e799-b875-9b358ef7aff9@gmx.net> <20161015132249.607b374c@fabiankeil.de>
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Am 2016-10-15 um 13:22 schrieb Fabian Keil: > Michael Osipov <1983-01-06@gmx.net> wrote: > >> Am 2016-10-14 um 11:43 schrieb Fabian Keil: >>> Michael Osipov <1983-01-06@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. Ah ok, I need to switch physically to that machine because SSH is not possible. I don't mind to read the DTrace tutorial but what exactly should I trace? sshd? >> 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. I will switch from 11.0-RELEASE to 11.0-STABLE via Subversion first, rebuild world and kernel and then apply your patches. Hand on. Michael
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