From owner-freebsd-current@FreeBSD.ORG Fri Mar 21 15:53:54 2014 Return-Path: Delivered-To: freebsd-current@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [8.8.178.115]) (using TLSv1 with cipher ADH-AES256-SHA (256/256 bits)) (No client certificate requested) by hub.freebsd.org (Postfix) with ESMTPS id DF131309 for ; Fri, 21 Mar 2014 15:53:54 +0000 (UTC) Received: from mail-wi0-x22f.google.com (mail-wi0-x22f.google.com [IPv6:2a00:1450:400c:c05::22f]) (using TLSv1 with cipher ECDHE-RSA-RC4-SHA (128/128 bits)) (No client certificate requested) by mx1.freebsd.org (Postfix) with ESMTPS id 784FEC81 for ; Fri, 21 Mar 2014 15:53:54 +0000 (UTC) Received: by mail-wi0-f175.google.com with SMTP id cc10so644235wib.8 for ; Fri, 21 Mar 2014 08:53:53 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=googlemail.com; s=20120113; h=date:from:to:subject:message-id:in-reply-to:references:mime-version :content-type:content-transfer-encoding; bh=Zclgr3PaBytBD8g5WILrzGASOG+Ak8mlQk33X8u095A=; b=kBIonEwM9iPdI2iM7GM8TLyXdoWA2q5QBTl/Wzwpch+itWh4RLTIw9LuMdKfeCZpL6 x0syMbF4Yc/MZk2RtFbsISHtaqPUVDIiEasJL/fLFQBaaWiauCvQNULu3OGJxOsGC2ou jBWisPVoM9jN4Y5fig63uMSuf2L3BAv3ahnhWHDaYqy6u61dGArZNgwHPqLVQSzlFxqN N4QlkgukggmfVommU2PzsNXCpIssNo/TnkPCE7a3nXO1vzsQosBC7cvlFPO1/OPdCsRU Ojej9Os6T/N3MZPKzLi+sKy0wnWOeYiy0PXOLDKaLYYtAtYcZWf/SJnm8knw8xobUh5m YucQ== X-Received: by 10.180.188.229 with SMTP id gd5mr3369300wic.54.1395417233018; Fri, 21 Mar 2014 08:53:53 -0700 (PDT) Received: from gumby.homeunix.com ([94.195.197.72]) by mx.google.com with ESMTPSA id jd2sm5916921wic.9.2014.03.21.08.53.51 for (version=SSLv3 cipher=RC4-SHA bits=128/128); Fri, 21 Mar 2014 08:53:51 -0700 (PDT) Date: Fri, 21 Mar 2014 15:53:48 +0000 From: RW To: freebsd-current@freebsd.org Subject: Re: geli TRIM support Message-ID: <20140321155348.2945e05e@gumby.homeunix.com> In-Reply-To: References: X-Mailer: Claws Mail 3.9.3 (GTK+ 2.24.22; amd64-portbld-freebsd10.0) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-BeenThere: freebsd-current@freebsd.org X-Mailman-Version: 2.1.17 Precedence: list List-Id: Discussions about the use of FreeBSD-current List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 21 Mar 2014 15:53:54 -0000 On Thu, 20 Mar 2014 19:34:04 +0000 Mike C. wrote: > I was actually googling about this yesterday and found no more info > then the thread you posted. > > So its seems that nothing was done related to this so far? > > Which means using trim+geli is problematic. These days SSD devices have static wear-levelling so you don't need to maximize the number of free blocks, just maintain a small pool. You can do that by not partitioning the whole device and leaving a few percent unused. I'm not sure what you would do if the device had already been written to though, if FreeBSD has a command to trim a device I don't know what it is. You could just use Linux's hdparm from a live CD. You should also be OK if you have a non-geli UFS partition with sufficient free space on the same device. > I was using my ssd with UFS+trim+geli in my laptop. But even before > noticing the lack of support changed my setup... since the laptop has > both a ssd and hdd I am now using zfs+geli in the hdd. I have 2 > partitions in the ssd and I'm using it for log/cache. I've been considering that, but I did have a couple of concerns: 1. l2arc sounds like it would be much less effective outside of servers because, AFAIK, the cache doesn't survive a reboot. 2. the l2arc cache turns reads on the filesystem into writes to the SSD.