Date: Mon, 21 Mar 2016 12:01:09 -0600 From: John Nielsen <lists@jnielsen.net> To: Paul Vixie <paul@redbarn.org> Cc: =?utf-8?B?0KHQtdGA0LPQtdC5INCc0LDQvNC+0L3QvtCy?= <mrqwer88@gmail.com>, Sergei Mamonov <mamonov@fastvps.ru>, "freebsd-virtualization@freebsd.org" <freebsd-virtualization@freebsd.org> Subject: Re: ZFS subvolume support inside Bhyve vm Message-ID: <06FE3C97-1165-482E-8DC3-1B3A2D6C4A91@jnielsen.net> In-Reply-To: <56E211FE.2060700@redbarn.org> References: <CALgsdbcXxAnfkKnU9CuOE-pj0sJJpQ7-XFd6R0bFEeKB-maDRw@mail.gmail.com> <56E206FE.3080000@redbarn.org> <CAG2oxtrnmYpPznFiBfPARG69wBiCWdqn6ch_E64X=M33sVN-uw@mail.gmail.com> <56E211FE.2060700@redbarn.org>
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> On Mar 10, 2016, at 5:31 PM, Paul Vixie <paul@redbarn.org> wrote: >=20 > =D0=A1=D0=B5=D1=80=D0=B3=D0=B5=D0=B9 =D0=9C=D0=B0=D0=BC=D0=BE=D0=BD=D0=BE= =D0=B2 wrote: >> Hello! >>=20 >> Yes - zvols looks awesome. But what driver you use for it? >=20 > virtio-blk. >=20 >> And what >> about disk usage overhead in guest? >=20 > ufs on zvol is faster, either in the parent or a bhyve using = virtio-blk, than zfs. at least for writing, which is my dominant work = load. i expect that this is due to zfs's compression logic rather than = anything having to do with creating/extending files to accommodate = writes. >=20 >> virtio-blk doesnt support fstrim (ahci-hd support it, but slower? = "/At >> this point virtio-blk is indeed faster then ahci-hd on high IOPS/"). >> In linux && kvm we try used virtio-scsi driver with support fstrim, = but >> how I see it not availble now in 10-2 stable for bhyve. >> And I not lonely with this question - >> = https://lists.freebsd.org/pipermail/freebsd-virtualization/2015-March/0034= 42.html >=20 > i'm just going to live without fstrim until it's supported in = virtio-blk. i know that this option isn't available to everybody, but at = the moment storage is cheap enough to waste. At the risk of getting farther off-topic.. Virtio-blk can't and won't support fstrim. If/when bhyve were to have = virtio-scsi support that could work with trim, but last I was aware = there wasn't a whole lot of momentum in that direction. The virtual AHCI = controller in bhyve does support trim and performs remarkably well. = That's what I use for my vol-backed VMs and I haven't had any = complaints. Worth testing, IMO. JN
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