From owner-freebsd-fs@FreeBSD.ORG Tue Jun 15 14:04:18 2010 Return-Path: Delivered-To: freebsd-fs@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id AA8A31065672 for ; Tue, 15 Jun 2010 14:04:18 +0000 (UTC) (envelope-from jdc@koitsu.dyndns.org) Received: from qmta06.emeryville.ca.mail.comcast.net (qmta06.emeryville.ca.mail.comcast.net [76.96.30.56]) by mx1.freebsd.org (Postfix) with ESMTP id 92DBB8FC23 for ; Tue, 15 Jun 2010 14:04:18 +0000 (UTC) Received: from omta15.emeryville.ca.mail.comcast.net ([76.96.30.71]) by qmta06.emeryville.ca.mail.comcast.net with comcast id WDFk1e0031Y3wxoA6E4Jls; Tue, 15 Jun 2010 14:04:18 +0000 Received: from koitsu.dyndns.org ([98.248.46.159]) by omta15.emeryville.ca.mail.comcast.net with comcast id WE4H1e0023S48mS8bE4H7r; Tue, 15 Jun 2010 14:04:17 +0000 Received: by icarus.home.lan (Postfix, from userid 1000) id D0C479B418; Tue, 15 Jun 2010 07:04:16 -0700 (PDT) Date: Tue, 15 Jun 2010 07:04:16 -0700 From: Jeremy Chadwick To: Thomas Steen Rasmussen Message-ID: <20100615140416.GA48384@icarus.home.lan> References: <4C177E69.3020204@gibfest.dk> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <4C177E69.3020204@gibfest.dk> User-Agent: Mutt/1.5.20 (2009-06-14) Cc: freebsd-fs@freebsd.org Subject: Re: ZFS l2arc and HAST ? newbie question X-BeenThere: freebsd-fs@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Filesystems List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 15 Jun 2010 14:04:18 -0000 On Tue, Jun 15, 2010 at 03:21:45PM +0200, Thomas Steen Rasmussen wrote: > But what about slog and cache devices, currently on SSD disks for > performance reasons ? It doesn't really make sense to synchronize > a cache disk over the network, does it ? > > Could I build the zpool with the SSD disks directly (without > HAST) and would ZFS survive an export/import on the other host, > when the cache disks are suddently different ? I am thinking cache > only here, not slog. Taken from zpool(8): If a read error is encountered on a cache device, that read I/O is reissued to the original storage pool device, which might be part of a mirrored or raidz configuration. The content of the cache devices is considered volatile, as is the case with other system caches. So I would say use the local system's SSDs for "cache" and leave the rest for HAST. With regards to "Intent Logs" -- I simply do not know. -- | Jeremy Chadwick jdc@parodius.com | | Parodius Networking http://www.parodius.com/ | | UNIX Systems Administrator Mountain View, CA, USA | | Making life hard for others since 1977. PGP: 4BD6C0CB |