From owner-freebsd-questions@FreeBSD.ORG Thu May 21 16:48:54 2015 Return-Path: Delivered-To: freebsd-questions@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [8.8.178.115]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by hub.freebsd.org (Postfix) with ESMTPS id F08FEDBB for ; Thu, 21 May 2015 16:48:54 +0000 (UTC) Received: from mail-lb0-x22f.google.com (mail-lb0-x22f.google.com [IPv6:2a00:1450:4010:c04::22f]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (Client CN "smtp.gmail.com", Issuer "Google Internet Authority G2" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id 791FE16C6 for ; Thu, 21 May 2015 16:48:54 +0000 (UTC) Received: by lbcmx3 with SMTP id mx3so22501754lbc.1 for ; Thu, 21 May 2015 09:48:52 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :content-type; bh=Nupniol+VbQ0UuB8pC2mp61m/f2HshnWLX629RnZY90=; b=XRgt5sSRF7fla2Xw75liFMsjvafWYJSoumWVeNlRblSJjTW4OWVnoVy5OYxi0IfcW/ uxy9sxHQL6e0jrSyhWwql2bb5IsjQ0bj+XwWYx8YYLDEKmELu/RWOEQgn5J4VXIaro8Q nl+nVC8FJxTcGaZ3mCIV7wzRpjh3sXDWyaJe6b7P/lPy55DjxoiyPnLb4XHOjcA7WLWR s9rBLZ8j2JxpKiBjLUUNNoyYxLYLUGp2hdgg+jJQd1kClLTo9rI0y48HR0EevtRYdEUv uX1InAMd0h4M9uvRcmqNXG78tztlX3gHKTey5pqVqwHH5YazuFNETBQhBYZQ5HWOlMD2 RxWw== MIME-Version: 1.0 X-Received: by 10.152.23.4 with SMTP id i4mr2976644laf.51.1432226932394; Thu, 21 May 2015 09:48:52 -0700 (PDT) Received: by 10.25.42.146 with HTTP; Thu, 21 May 2015 09:48:52 -0700 (PDT) In-Reply-To: References: Date: Thu, 21 May 2015 09:48:52 -0700 Message-ID: Subject: Re: SLOG and SSDs: are "super" capacitors really needed? From: Chris Stankevitz To: freebsd-questions Content-Type: text/plain; charset=UTF-8 X-BeenThere: freebsd-questions@freebsd.org X-Mailman-Version: 2.1.20 Precedence: list List-Id: User questions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 21 May 2015 16:48:55 -0000 On Thu, May 21, 2015 at 8:38 AM, Chris Stankevitz wrote: > Question: do SSD drives report the write has "completed" only after > the data has been burned into non-volatile storage? Apparently the answer to this is "no. SSDs report the write is completed long before the data has made its way to non-volatile storage": https://www.usenix.org/system/files/conference/fast13/fast13-final80.pdf Thank you for the replies, Chris