Date: Tue, 23 Aug 2016 05:54:52 +1000 From: Jan Mikkelsen <janm@transactionware.com> To: Kevin Oberman <rkoberman@gmail.com> Cc: "freebsd-emulation@freebsd.org" <emulation@freebsd.org> Subject: Re: Odd behavior with virtualbox-ose-4.3.38 Message-ID: <59E9F6CE-0F2B-40E1-B78D-AF9DFBCED280@transactionware.com> In-Reply-To: <CAN6yY1v%2BfxZKYexP5m=xUtqaoPjm1zM_4LHXtY5YD_2qAecOoQ@mail.gmail.com> References: <CAN6yY1vn_o%2B=bX7MRNwnurp_G%2BDRhD3sfSS63-1hx4JbYsVaSw@mail.gmail.com> <CAN6yY1sG92DUR0-7Y_wE-r94%2B22JZszgcsOy=XrY=J77njUC_Q@mail.gmail.com> <2418C811-3C6E-4837-B6A5-51DB4C425EB4@transactionware.com> <CAN6yY1v%2BfxZKYexP5m=xUtqaoPjm1zM_4LHXtY5YD_2qAecOoQ@mail.gmail.com>
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Hi, > On 23 Aug 2016, at 02:25, Kevin Oberman <rkoberman@gmail.com> wrote: > > On Mon, Aug 22, 2016 at 1:50 AM, Jan Mikkelsen <janm@transactionware.com <mailto:janm@transactionware.com>> wrote: > Do you have aio loaded or compiled into your kernel? If so, does it keep happening without aio? > [ … ] > Thanks for the suggestion, but, no. This is on my trusty Lenovo T520 laptop and no aio to be found. My configuration is just: > include GENERIC > ident GENERIC_BSD4 > > nooptions SCHED_ULE # ULE scheduler > options SCHED_4BSD # 4BSD scheduler > > I still can't be sure if the problem was triggered by the move to VB 5 or t FreeBSD-11 (or a combination of both). Yes, the problem could be in many places. However, if you’ve gone to FreeBSD 11, you have more aio than you think. From UPDATING: 20160301: The AIO subsystem is now a standard part of the kernel. The VFS_AIO kernel option and aio.ko kernel module have been removed. Due to stability concerns, asynchronous I/O requests are only permitted on sockets and raw disks by default. To enable asynchronous I/O requests on all file types, set the vfs.aio.enable_unsafe sysctl to a non-zero value. Are you running the VM against a raw disk device? You can check the VBox.log output — If you are not using aio, you should see an entry like this: AIO: Async I/O manager not supported (rc=VERR_NOT_SUPPORTED). Falling back to simple manager If you are using AIO, you will should see entries like: AIOMgr: Default manager type is "Async" AIOMgr: Default file backend is “NonBuffered" AIO issues were not a big issue for a long time but some recent updates to 4.3.something (or other environmental issues, possibly load) led me to turn aio off on a bunch of 10.x machines running a significant number of VMs (~25). I’m have been curious about whether the aio change would cause problems with an upgrade to 11. Regards, Jan.
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