From mboxrd@z Thu Jan 1 00:00:00 1970 Content-Type: multipart/mixed; boundary="===============7306384919745131718==" MIME-Version: 1.0 From: Harris, James R Subject: Re: [SPDK] Handling of physical disk removals Date: Fri, 01 Jun 2018 16:54:03 +0000 Message-ID: In-Reply-To: CAKye4QbhELsBk2tdaAy1pW75P6Qq5Tcbt2ds97oujp1==s=Gvg@mail.gmail.com List-ID: To: spdk@lists.01.org --===============7306384919745131718== Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable From: SPDK on behalf of Baruch Even Reply-To: Storage Performance Development Kit Date: Friday, June 1, 2018 at 1:25 AM To: Storage Performance Development Kit Subject: Re: [SPDK] Handling of physical disk removals [=E2=80=A6] In regards to your concerns on I/O splitting - I think step one is making s= ure the driver has APIs to expose any device-specific characteristics such = as sectors per stripe. Step two is measuring the overhead of the splitting= logic when splitting is not required. Based on those measurements, we can= consider optimizations and/or evaluate a bypass mode. The bypass mode see= ms important to Weka.io =E2=80=93 would you like to submit an RFC for what = this bypass mode might look like in more detail? What is needed for the RFC? It doesn=E2=80=99t need to be especially formal. Basically, what your new = API would look like and how it would impact the existing code at a reasonab= le level of detail. Also, what tests you would plan to add to automate tes= ting of the new API. An RFC typically comes with an assumption that the au= thor plans to carry the work forward if and when a consensus has been reach= ed. If that assumption is not correct, it is best to clarify that up front. Any kind of empirical performance data is critical. I=E2=80=99m really int= erested in seeing it. The existing driver can get >4M IO/s on a single Xeo= n core, so the extra complexity and maintenance burden of the new API has t= o show demonstrable improvements. Hopefully there would be no changes to t= he existing API, but if there are, that=E2=80=99s another data point that w= ould need to be considered. Baruch -- [https://docs.google.com/uc?export=3Ddownload&id=3D1w6mlhCJZRlvqVOKRoulFtal= U3TMY41VY&revid=3D0Bw_6cJeSSMVJR2JMQzdxV3VqVi9IWFNDM1FVcnFoRlc2NkJzPQ] Baruch Even, Software Developer E baruch(a)weka.io www.weka.io --===============7306384919745131718== Content-Type: text/html MIME-Version: 1.0 Content-Transfer-Encoding: base64 Content-Disposition: attachment; filename="attachment.html" PGh0bWwgeG1sbnM6dj0idXJuOnNjaGVtYXMtbWljcm9zb2Z0LWNvbTp2bWwiIHhtbG5zOm89InVy bjpzY2hlbWFzLW1pY3Jvc29mdC1jb206b2ZmaWNlOm9mZmljZSIgeG1sbnM6dz0idXJuOnNjaGVt YXMtbWljcm9zb2Z0LWNvbTpvZmZpY2U6d29yZCIgeG1sbnM6bT0iaHR0cDovL3NjaGVtYXMubWlj cm9zb2Z0LmNvbS9vZmZpY2UvMjAwNC8xMi9vbW1sIiB4bWxuczptdj0iaHR0cDovL21hY1ZtbFNj aGVtYVVyaSIgeG1sbnM9Imh0dHA6Ly93d3cudzMub3JnL1RSL1JFQy1odG1sNDAiPg0KPGhlYWQ+ DQo8bWV0YSBodHRwLWVxdWl2PSJDb250ZW50LVR5cGUiIGNvbnRlbnQ9InRleHQvaHRtbDsgY2hh cnNldD11dGYtOCI+DQo8bWV0YSBuYW1lPSJUaXRsZSIgY29udGVudD0iIj4NCjxtZXRhIG5hbWU9 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