Date: Sat, 8 Feb 2014 15:19:04 -0500 From: Aryeh Friedman <aryeh.friedman@gmail.com> To: Adam Vande More <amvandemore@gmail.com> Cc: FreeBSD virtualization <freebsd-virtualization@freebsd.org> Subject: Re: Report of my virtual network lab migrated from virtualbox to bhyve Message-ID: <CAGBxaX=QuyMxC95RQDJ=6L4GMeh_Szyfj8yT-wtNeABWD2seQg@mail.gmail.com> In-Reply-To: <CAGBxaXmFhZtJECH5-d_nY=e2ek=1ANFTsLTv6EHAFXEA34Cskw@mail.gmail.com> References: <CA%2Bq%2BTcqw7uHLV3=DeZF4=i0hbmECkPP-d5-4ReSQqKCV-JaJ=Q@mail.gmail.com> <52F5363D.8040102@freebsd.org> <CA%2Bq%2BTcrZZb5o51F4pvLtxKM%2BNvO6SdVEQk_UMLLYSF8JfK6gpg@mail.gmail.com> <CA%2BtpaK2QCoxRocF7=zY3j9VETM7SJqFSVwpFGC0DuPSgFKJwZA@mail.gmail.com> <CAGBxaXmgzLncYi-5YPamqXD2nYvHi_eMUGQQe3hDmPEdyxd5%2Bw@mail.gmail.com> <CA%2BtpaK1VEw%2BRMfqLBukaXXADXtW82gC73TzXtiVGhSc9DrN=Qw@mail.gmail.com> <CAGBxaXk=NxY%2BENmCaW_GmHJCxYDR1-W-41W__xooTjz=ic1UEg@mail.gmail.com> <CA%2BtpaK3WvyZ2_Y5XunLV57hhwqpDFoRqQSZAxF=SKS4wib0t0A@mail.gmail.com> <CAGBxaXmFhZtJECH5-d_nY=e2ek=1ANFTsLTv6EHAFXEA34Cskw@mail.gmail.com>
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On Sat, Feb 8, 2014 at 3:14 PM, Aryeh Friedman <aryeh.friedman@gmail.com>wrote: > > > > On Sat, Feb 8, 2014 at 3:01 PM, Adam Vande More <amvandemore@gmail.com>wrote: > >> >> On Sat, Feb 8, 2014 at 6:51 AM, Aryeh Friedman <aryeh.friedman@gmail.com>wrote: >>> >>> bhyve blindly read/writes into the middle of the file without consulting >>> the filesystem and thus bypassing any things like sparse fill in.... namely >>> all you gain is a few seconds of startup time (matter of fact I think >>> truncate might use sparse allocation [i.e. attempting to read into the >>> middle with guest OS control will result in potentially seeing host data]) >>> >> >> If this is true then there is a *critical* security issue. >> >> Using sparse files isn't to gain performance, it's to conserve disk >> space. Using md devices backed by sparse images would accomplish this. If >> the sparsify app works on FreeBSD, then there should be no problem using >> those type of volumes. >> >> > It sounds almost identical to the qcow2 security issue being discussed on > qemu-devel@qemu.org recently. This might be a *HUGE* win for bhyve then > in considering that it's default format is raw (should ahci-hdd be the > default?). devel/qemu (not sure about -dev) uses qcow2 as a default and > when playing with it on other OS's I found that it seemed to default to > that also. It is my understand that most of the open source cloud > platforms use qcow2 as their default also (I remember this from an attempt > to install openstack grizzly last summer... I have not checked havana > though... can any of the freebsd-openstack confirm this?). > Forgot to mention that the host OS's disk scheduling also gives a brief window of opportunity during the time after the inode is made and the old contents wiped due to the size of the file -- Aryeh M. Friedman, Lead Developer, http://www.PetiteCloud.org
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