From owner-freebsd-hackers@FreeBSD.ORG Thu Apr 26 17:25:09 2012 Return-Path: Delivered-To: freebsd-hackers@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 7F302106566B for ; Thu, 26 Apr 2012 17:25:09 +0000 (UTC) (envelope-from yanegomi@gmail.com) Received: from mail-vb0-f54.google.com (mail-vb0-f54.google.com [209.85.212.54]) by mx1.freebsd.org (Postfix) with ESMTP id 367E28FC0A for ; Thu, 26 Apr 2012 17:25:09 +0000 (UTC) Received: by vbmv11 with SMTP id v11so1474964vbm.13 for ; Thu, 26 Apr 2012 10:25:08 -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=Ggg27udiIiJk1HrHPCbdMB6UY3S09StkC2gEnZ7Nvy0=; b=KXRuF8t+CHRYslSwzo7NM6w5nWATOWgFoWu5QFxqvWj0lR6iJrhVx2UwVZ0lSokaMg TWzTa4E8C/fwN0w2sEWo0KG7/5PloChkjBFsshpmHQ+aN/goeDi5CLo6T8gNHN5nt+7L I53YpCG0MX9TMiQIIhrEScpG+oXGKw8KEEdVKoVpXpg8XRn3V0ObdQgTG1aSz/O/WHuC Wad5y6m63Qr9TWFEFcAF29E0Ww9gdfygd0rofAxhAppF6Jq3oU5nT/amyOR5j+SkQiQC 2Z6rf4vqVyd1Wrwv2HXtOQC9J4tSG0clFjlf7bYhFWwvM2nnbTPTLdp0HS3NGL0cOiIn 2Fqw== MIME-Version: 1.0 Received: by 10.52.73.132 with SMTP id l4mr6828934vdv.4.1335461108324; Thu, 26 Apr 2012 10:25:08 -0700 (PDT) Received: by 10.220.230.135 with HTTP; Thu, 26 Apr 2012 10:25:08 -0700 (PDT) In-Reply-To: References: Date: Thu, 26 Apr 2012 10:25:08 -0700 Message-ID: From: Garrett Cooper To: Wojciech Puchar Content-Type: text/plain; charset=ISO-8859-1 Cc: freebsd-hackers@freebsd.org Subject: Re: best possible GJOURNAL device? X-BeenThere: freebsd-hackers@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Technical Discussions relating to FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 26 Apr 2012 17:25:09 -0000 On Thu, Apr 26, 2012 at 10:16 AM, Wojciech Puchar wrote: > http://www.vikingmodular.com/products/arxcis/ddr3/ddr3.html > > or ZFS ZIL device for ZFS fans. > > anyone know exactly how it is visible and how it works? In general devices like these that I've dealt with in the past are presented as SATA or SAS devices, but some devices require additional drivers (take Ramdrives devices for instance). > isn't BIOS clearing out memory on reboot? Depends on the BIOS, the settings set in the BIOS, etc. > FreeBSD is but it can be patched easily. I wouldn't depend on volatile memory working in a non-volatile manner unless it's battery backed (which companies like Ramdrive, STEC, Viking, etc do) and in which case all you're doing (depending on how the device is designed) is delaying writes out to non-volatile (NAND/NOR flash) or another non-volatile medium (USB thumbdrive? etc... I vaguely remember seeing a vendor doing something "clever" like that...). > How to get DRAM controller mapping i mean what DIMM is at what address? What is located where should be opaque if the designer designed it properly (otherwise a driver will need to be added to interface with the device if the vendor is trying to be clever or is not fully conforming to ATA/SCSI standards). Thanks, -Garrett