Date: Fri, 27 Mar 2015 11:00:33 -0600 From: John Nielsen <lists@jnielsen.net> To: freebsd-virtualization@freebsd.org Cc: Julian Hsiao <madoka@nyanisore.net> Subject: Re: Bhyve storage improvements (was: Several bhyve quirks) Message-ID: <BB23F660-BB98-480D-BA77-EABD11E712A1@jnielsen.net> In-Reply-To: <98136D5B-297B-4538-8EF4-EA2872C6640B@jnielsen.net> References: <5515270A.7050408@FreeBSD.org> <98136D5B-297B-4538-8EF4-EA2872C6640B@jnielsen.net>
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On Mar 27, 2015, at 10:47 AM, John Nielsen <lists@jnielsen.net> wrote: > On Mar 27, 2015, at 3:46 AM, Alexander Motin <mav@freebsd.org> wrote: >=20 >>> I've always assumed virtio driver > emulated driver so it didn't = occur >>> to me to try ahci-hd. >>=20 >> I've just merged to FreeBSD stable/10 branch set of bhyve changes = that >> should significantly improve situation in the storage area. >>=20 >> virtio-blk driver was fixed to work asynchronously and not block = virtual >> CPU, that should fix many problems with performance and = interactivity. >> Both virtio-blk and ahci-hd drivers got ability to execute multiple = (up >> to 8) requests same time, that should proportionally improve parallel >> random I/O performance on wide storages. At this point virtio-blk is >> indeed faster then ahci-hd on high IOPS, and they both are faster = then >> before. >>=20 >> On the other side ahci-hd driver now got TRIM support to allow = freeing >> unused space on backing ZVOL. Unfortunately there is no any = TRIM/UNMAP >> support in virtio-blk API to allow the same. >>=20 >> Also both virtio-blk and ahci-hd drivers now report to guest logical = and >> physical block sizes of underlying storage, that allow guests = properly >> align partitions and I/Os for best compatibility and performance. >=20 > Mav, thank you very much for all this great work and for the concise = summary. TRIM on AHCI makes it compelling for a lot of use cases despite = the probable performance hit. >=20 > Does anyone have plans (or know about any) to implement virtio-scsi = support in bhyve? That API does support TRIM and should retain most or = all of the low-overhead virtio goodness. Okay, some belated googling reminded me that this has been listed as an = "open task" in the last couple of FreeBSD quarterly status reports and = discussed at one or more devsummits. I'd still be interested to know if = anyone's actually contemplated or started doing the work though. :) JN
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