From owner-freebsd-fs@FreeBSD.ORG Wed Nov 14 04:27:14 2012 Return-Path: Delivered-To: freebsd-fs@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [69.147.83.52]) by hub.freebsd.org (Postfix) with ESMTP id 8A64EBCF for ; Wed, 14 Nov 2012 04:27:14 +0000 (UTC) (envelope-from bryan@shatow.net) Received: from secure.xzibition.com (secure.xzibition.com [173.160.118.92]) by mx1.freebsd.org (Postfix) with ESMTP id 2B4C48FC12 for ; Wed, 14 Nov 2012 04:27:13 +0000 (UTC) DomainKey-Signature: a=rsa-sha1; c=nofws; d=shatow.net; h=message-id :date:from:mime-version:to:cc:subject:references:in-reply-to :content-type:content-transfer-encoding; q=dns; s=sweb; b=z5jvbZ nYmwJwX/0Cdi+b7Gik412oi7SX1FXsAgYBuBA07559DObt7bsouqLpUnj4o2LZqZ xfbKzFZPuJemhqh04t5n2SyxyIKmiQltIjwVo5VfdpRe1JpIYX9J+dRtKLVgihXH PAurqyOZbnWwh+EegcROubViGM2ZJLYNd8JfI= DKIM-Signature: v=1; a=rsa-sha256; c=simple; d=shatow.net; h=message-id :date:from:mime-version:to:cc:subject:references:in-reply-to :content-type:content-transfer-encoding; s=sweb; bh=iTF9KVd6zwV4 ucx9SSyI3buAOJR/eB/XeFO91YkX/PQ=; b=Av6IdI3WKzGRLC/dDGtf+aMsJfZq q4HLyem96z0h5i+fVT5AkVu5vhQdRb4JWuu72scKgAQdXEYgxaqnfWuoXRtkSb0r g27TWlndc/35a8K4ikcasUBl6B0G8kP0qp3ujuODM8OdyGy2+8i044egNrlcMb3/ 1MDicMCpILXJOJ4= Received: (qmail 44339 invoked from network); 13 Nov 2012 22:27:12 -0600 Received: from unknown (HELO ?10.10.0.115?) (bryan@shatow.net@10.10.0.115) by sweb.xzibition.com with ESMTPA; 13 Nov 2012 22:27:12 -0600 Message-ID: <50A31D9A.7020200@shatow.net> Date: Tue, 13 Nov 2012 22:27:06 -0600 From: Bryan Drewery User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:16.0) Gecko/20121026 Thunderbird/16.0.2 MIME-Version: 1.0 To: Chris BeHanna Subject: Re: SSD recommendations for ZFS cache/log References: <57ac1f$gf3rkl@ipmail05.adl6.internode.on.net> <943159E4-8824-4767-96E1-89E8EC69DCDF@behanna.org> In-Reply-To: <943159E4-8824-4767-96E1-89E8EC69DCDF@behanna.org> X-Enigmail-Version: 1.4.5 OpenPGP: id=3C9B0CF9; url=http://www.shatow.net/bryan/bryan.asc Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Cc: FreeBSD FS X-BeenThere: freebsd-fs@freebsd.org X-Mailman-Version: 2.1.14 Precedence: list List-Id: Filesystems List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 14 Nov 2012 04:27:14 -0000 On 11/13/2012 10:18 PM, Chris BeHanna wrote: > On Nov 13, 2012, at 21:51, Stephen McKay wrote: > >> [...lots of good advice about measuring, and lots of good advice about L2ARC...] >> >> I have no way to determine in advance the behaviour of an SSD on >> power failure so I assume all the ones I can afford have bad >> behaviour. :-) I know that expensive ones contain capacitors so >> that power failures do not corrupt their contents. By the nature >> of advertising (from which we know that any feature not excessively >> hyped must therefore not be supported), we must conclude that other >> SSDs by normal operation corrupt blocks on power failure. > > If you'll pardon what may be an ignorant question, does this matter if you have your machine on a UPS, especially if you run upsmon or nut to do a graceful shutdown when there are n minutes of battery remaining? > I've had more than 1 UPS battery die on me, resulting in instant shutoff. > Thanks, >