Date: Tue, 6 Sep 2016 09:27:38 -0700 From: Kevin Oberman <rkoberman@gmail.com> To: Jim Ohlstein <jim@ohlste.in> Cc: Konstantin Belousov <kostikbel@gmail.com>, Alan Somers <asomers@freebsd.org>, FreeBSD Stable ML <freebsd-stable@freebsd.org>, np@freebsd.org Subject: Re: AIO not working on NFS share - ? Regression Message-ID: <CAN6yY1tKy1NnnDqFLP-sSDPaT6TjTj4NfzX8_SGt0db%2B2RLH=w@mail.gmail.com> In-Reply-To: <87af720e-7506-d1de-9f93-f9d5a2589f7a@ohlste.in> References: <6c9093cd-1323-77b1-b27e-f53b58ec86e4@ohlste.in> <CAOtMX2iWaYq9ujgZ3bWx3YYo5ESgz5hp6epo=rbro7yDU2QESQ@mail.gmail.com> <20160905203412.GQ83214@kib.kiev.ua> <87af720e-7506-d1de-9f93-f9d5a2589f7a@ohlste.in>
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On Mon, Sep 5, 2016 at 1:41 PM, Jim Ohlstein <jim@ohlste.in> wrote:
> Hello,
>
> On 09/05/2016 04:34 PM, Konstantin Belousov wrote:
>
>> On Mon, Sep 05, 2016 at 02:26:30PM -0600, Alan Somers wrote:
>>
>>> Just to get your webserver out of the picture, could you please try
>>> running the aio test suite on an NFS share? Do it like this:
>>> $ cd /usr/tests/sys/aio
>>> $ export TMPFS=/path/to/some/nfs/share
>>> $ kyua test
>>>
>> By default, unsafe aio is disabled, i.e. aio where the operation is not
>> really async and can usurp kernel thread for indefinite amount of time.
>> Non-local filesystems accesses are classified as unsafe, since their
>> completion is controlled by remote host.
>>
>
> Setting vfs.aio.enable_unsafe to 1 solved the problem, though I don't
> recall this being necessary in the past.
>
> Thanks for the quick responses and fix.
>
>
>
>>
>>> -Alan
>>>
>>> On Mon, Sep 5, 2016 at 2:14 PM, Jim Ohlstein <jim@ohlste.in> wrote:
>>>
>>>> Hello,
>>>>
>>>> For sometime now we've used a backend (non-internet accessible) server
>>>> to
>>>> generate static content that is shared via NFS to a front-end server for
>>>> internet access. Both machines use ZFS exclusively.
>>>>
>>>> The webserver is nginx and we had AIO set to on, with the AIO module
>>>> built
>>>> into the kernel.In 10.x it "just worked".
>>>>
>>>> About two weeks ago I upgraded that backend machine to 11-STABLE in
>>>> order to
>>>> start building packages for 11. I've just updated it again to r305417. I
>>>> don't recall it not working as expected.
>>>>
>>>> More recently I upgraded the front-end machine to 11-STABLE @r305311.
>>>> Since
>>>> then, AIO is not working and I get a critical error in the nginx logs
>>>> like
>>>> this:
>>>>
>>>> 2016/09/05 15:58:02 [crit] 21145#0: *649 aio_read("/path/to/file")
>>>> failed
>>>> (45: Operation not supported) while sending response to client ...
>>>>
>>>> In 11 AIO is built into the kernel by default, and I have confirmed
>>>> that it
>>>> works as expected in files from a local file system. Since the webserver
>>>> isn't aware that the file system in question is shared via NFS, it seems
>>>> this is an operating system issue.
>>>>
>>>
> --
> Jim Ohlstein
>
Could this also be related to AIO hanging VBox VMs? See
https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=212128
--
Kevin Oberman, Retired Network Engineer
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