From owner-freebsd-questions@FreeBSD.ORG Mon Jul 30 15:38:12 2012 Return-Path: Delivered-To: questions@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [69.147.83.52]) by hub.freebsd.org (Postfix) with ESMTP id 590E110656D4 for ; Mon, 30 Jul 2012 15:38:12 +0000 (UTC) (envelope-from gobble.wa@gmail.com) Received: from mail-wi0-f178.google.com (mail-wi0-f178.google.com [209.85.212.178]) by mx1.freebsd.org (Postfix) with ESMTP id D02358FC0A for ; Mon, 30 Jul 2012 15:38:11 +0000 (UTC) Received: by wibhr14 with SMTP id hr14so1489431wib.13 for ; Mon, 30 Jul 2012 08:38:10 -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 :cc:content-type; bh=VIJUuFvUg6POPNap2K6FVQh3s2JyWe99wNq2wcrETD4=; b=JhDPrq0e2KQPmxyLkqGnvugYjMramAg4l694YfX2ylky8EapFTnfx+jRdYp6Ywqe2y fLFLH9pEn+u7OPluUdh0zwGaXI9peXQgjTJ9anjLKhorGBGXjiyAZGkUGRsJrYte1jRJ fp7M3FqUSzbCxIMzWXYZlThJNZNsIYiH/kFRA41dWtda7dLcTTNIxYPSpxglyrnLqYpq E1/7MCjCcPrimyOQeLjR47/1MrMh6yeh4oRoWaJ1tewRj8Ab+c6C8bhnawPk/oYpzcX6 sDKlFozgInz6WPxQ+Y4l+VTU8RzM8PBaOA6kZUFPsTX7d3q+Ledi8Afrfb5TbjPnpd5K dJwQ== MIME-Version: 1.0 Received: by 10.216.167.135 with SMTP id i7mr5613123wel.97.1343662690725; Mon, 30 Jul 2012 08:38:10 -0700 (PDT) Received: by 10.216.67.131 with HTTP; Mon, 30 Jul 2012 08:38:10 -0700 (PDT) Received: by 10.216.67.131 with HTTP; Mon, 30 Jul 2012 08:38:10 -0700 (PDT) In-Reply-To: References: Date: Mon, 30 Jul 2012 08:38:10 -0700 Message-ID: From: Waitman Gobble To: Wojciech Puchar Content-Type: text/plain; charset=ISO-8859-1 X-Content-Filtered-By: Mailman/MimeDel 2.1.5 Cc: questions@freebsd.org, Vladimir Videscu Subject: Re: FreeBSD on SSD X-BeenThere: freebsd-questions@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: User questions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 30 Jul 2012 15:38:12 -0000 On Jul 28, 2012 11:42 AM, "Wojciech Puchar" wrote: >> >> The read-cache idea is very sound, mainly because by using it this way Seagate would not have to create a special set of >> instructions for installing and using the HDD. > > > I don't think that this drive cache is smart enough to really cache needed things and not flush that cache with useless data too often. > > i personally would prefer that drive to show up as 8GB disk and 750 GB disk. > > It would be easy to fit most of /usr in 8GB with even large set of software installed. > > when out of space then use softlinks and move not very used things (eg. documentation, non-yours locales, examples, some linarly accessed big files etc.) to disk. > > >> My final question would be : >> >> Seeing as the HDD only has a SATA connector, this would mean that the SSD part already has a memory control device that regulates >> access to that sector, whether it is a plain read-cache or not. This would imply that FreeBSD could communicate with the HDD >> normally, through the SATA connector, just like any regular HDD. > > > indeed. > > Such a drive is a good idea, but complete lack of documentation (how it operate) is not. > > You have to guess how this SSD-cache works because it is not documented. > > the other thing is erasing data. You want to sell that drive and clear your data by > > dd if=/dev/zero of=/dev/disk bs=1m > > but does it clear SSD cache? i don't think so. Someone sophisticated enough would perform raw read of cache chips and get cached data, which can actually be the most important part (things you work on often). > > _______________________________________________ > freebsd-questions@freebsd.org mailing list > http://lists.freebsd.org/mailman/listinfo/freebsd-questions > To unsubscribe, send any mail to " freebsd-questions-unsubscribe@freebsd.org" I've been using one of these drives for a few months, bought it because of bargain price and it sounded cool.. but its true there is little documentation, there seems to be no way to look at the SSD cache. I've read on some ng that it takes 5 to 10 boots to "learn" which files are loaded at boot.. maybe true. Also have not performed any comparison tests but maybe it boots faster. ... its not like instant on though. :) Waitman Gobble San Jose California