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Sat, 2 May 2026 09:45:46 -0400 (EDT) X-Mailer: MessagingEngine.com Webmail Interface List-Id: Discussion List-Archive: https://lists.freebsd.org/archives/freebsd-virtualization List-Help: List-Post: List-Subscribe: List-Unsubscribe: X-BeenThere: freebsd-virtualization@freebsd.org Sender: owner-freebsd-virtualization@FreeBSD.org MIME-Version: 1.0 X-ThreadId: AYfBX-KvMY3R Date: Sat, 02 May 2026 13:45:16 +0000 From: "Dave Cottlehuber" To: "Miroslav Lachman" <000.fbsd@quip.cz>, "Sean Eric Fagan" , freebsd-virtualization , "Chuck Tuffli" Cc: "Mark Johnston" Message-Id: <51b087ce-121a-4356-aba6-71ef1f0cad5c@app.fastmail.com> In-Reply-To: <4e4a795c-0dae-4e71-883a-0f3d45adb675@quip.cz> References: <4e4a795c-0dae-4e71-883a-0f3d45adb675@quip.cz> Subject: Re: bhyve and controlled errors Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable X-Spamd-Result: default: False [-4.08 / 15.00]; NEURAL_HAM_MEDIUM(-1.00)[-1.000]; NEURAL_HAM_LONG(-1.00)[-1.000]; NEURAL_HAM_SHORT(-0.99)[-0.990]; DMARC_POLICY_ALLOW(-0.50)[skunkwerks.at,reject]; R_DKIM_ALLOW(-0.20)[skunkwerks.at:s=fm1,messagingengine.com:s=fm3]; R_SPF_ALLOW(-0.20)[+ip4:202.12.124.128/27]; RCVD_IN_DNSWL_LOW(-0.10)[202.12.124.149:from]; MIME_GOOD(-0.10)[text/plain]; XM_UA_NO_VERSION(0.01)[]; ASN(0.00)[asn:151847, ipnet:202.12.124.0/24, country:AU]; DWL_DNSWL_NONE(0.00)[messagingengine.com:dkim]; FREEFALL_USER(0.00)[dch]; ARC_NA(0.00)[]; MIME_TRACE(0.00)[0:+]; RCVD_TLS_LAST(0.00)[]; MLMMJ_DEST(0.00)[freebsd-virtualization@freebsd.org]; FROM_EQ_ENVFROM(0.00)[]; FROM_HAS_DN(0.00)[]; RCPT_COUNT_FIVE(0.00)[5]; TO_MATCH_ENVRCPT_SOME(0.00)[]; RCVD_COUNT_THREE(0.00)[3]; TO_DN_ALL(0.00)[]; DKIM_TRACE(0.00)[skunkwerks.at:+,messagingengine.com:+] X-Spamd-Bar: ---- X-Rspamd-Queue-Id: 4g78Lj45Ysz3tNw On Tue, 7 Apr 2026, at 10:32, Miroslav Lachman wrote: > On 26/03/2026 15:56, Sean Eric Fagan wrote: >> I=E2=80=99d asked Mark about this and he suggested I bring it up on t= he list: >>=20 >> Has anyone thought about implementing controls / tunables to bhyve to= introduce errors? I am, most specifically right now, thinking about cau= sing disk I/O errors, or having requests dropped by the "hardware," to t= est error handling. >>=20 >> Last time I looked at the bhyve source code, it scared me, so if some= one else has looked at this, I=E2=80=99m love to know. > > I understand it would be nice to have it directly as a part of bhyve,=20 > but if you need something right now, you can try "gnop". > See man gnop(8): > Its main purpose is testing other GEOM classes, as it allows > forced provider removal and I/O error simulation with a given > probability. > > Or maybe someone with skill can reuse its code for bhyve feature. > > Kind regards > Miroslav Lachman Chuck Tuffli already did some work in this area: https://papers.freebsd.org/2019/bsdcan/tuffli-frankensteins_disk_drive/ https://bhyvecon.org/bhyveconOttawa2019-Chuck.pdf You should be able to find the related videos for these. A+ Dave