From owner-freebsd-fs@FreeBSD.ORG Thu May 12 08:58:05 2011 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 B088B106567A for ; Thu, 12 May 2011 08:58:05 +0000 (UTC) (envelope-from kraduk@gmail.com) Received: from mail-ww0-f50.google.com (mail-ww0-f50.google.com [74.125.82.50]) by mx1.freebsd.org (Postfix) with ESMTP id 3EC328FC1E for ; Thu, 12 May 2011 08:58:05 +0000 (UTC) Received: by wwc33 with SMTP id 33so1460113wwc.31 for ; Thu, 12 May 2011 01:58:04 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=gamma; h=domainkey-signature:mime-version:in-reply-to:references:date :message-id:subject:from:to:cc:content-type; bh=zismQCfy0mUCIfSmEvlGeSMHB/NeG1a9TKl3IfhZrz8=; b=WQcE56jw8sq7oJ7uk3Y0WfboQ2b67Y7pq6vZv88Wq02MfKzWcUgHG5wJUvl3pO8sUB F0y24dqoAFuisfPbk5GvadprsSpMWXU9mmVjTv9SM22Yh6YeYARDeIvrAizjJPrNlf4z EIEOoPsQ2HNoUyhypOrppr57B99J3f63qjzVA= DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :cc:content-type; b=TL8ZzzQv0RBQoh5nrQ96Yx9PwiFcPOjrope0+jb+3JjMKanwprw2M5t6QwcRAAeIQc F+KN0vaHC4p7ujg+0QWJnL5x2YP2qF5O/n7Q2O8feAvq8CU9OTZwLeXf85YzLXqvDJ60 6+Ejq3KFDHJ5oPCIL74zhNUbDJx1UlQvp8g7o= MIME-Version: 1.0 Received: by 10.216.14.212 with SMTP id d62mr1464049wed.91.1305190684314; Thu, 12 May 2011 01:58:04 -0700 (PDT) Received: by 10.216.93.70 with HTTP; Thu, 12 May 2011 01:58:04 -0700 (PDT) In-Reply-To: References: <4DCA5620.1030203@dannysplace.net> <4DCB455C.4020805@dannysplace.net> <4DCB81B8.6070301@digsys.bg> Date: Thu, 12 May 2011 09:58:04 +0100 Message-ID: From: krad To: =?UTF-8?Q?=C5=A0imun_Mikecin?= Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable X-Content-Filtered-By: Mailman/MimeDel 2.1.5 Cc: freebsd-fs Subject: Re: ZFS: How to enable cache and logs. 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: Thu, 12 May 2011 08:58:05 -0000 2011/5/12 =C5=A0imun Mikecin > > On 12. svi. 2011., at 08:44, Daniel Kalchev wrote: > > > On 12.05.11 05:26, Danny Carroll wrote: > >> > >> - Don't use SSD for the Log device. Write speed tends to be a proble= m. > > It all depends on your usage. You need to experiment, unfortunately. > > What is the alternative for log devices if you are not using SSD? > Rotating hard drives? > > AFAIK, two factors define the speed of log device: write transfer rate an= d > write latency. > You will not find a rotating hard drive that has a write latency anything > near the write latency of even a slowest SSD you can find on the market. > On the other hand, only a very few rotating hard drives have a write > transfer rate that can be compared to SSD's. > > _______________________________________________ > freebsd-fs@freebsd.org mailing list > http://lists.freebsd.org/mailman/listinfo/freebsd-fs > To unsubscribe, send any mail to "freebsd-fs-unsubscribe@freebsd.org" > ive seen an interesting article using 2x ram disks on two separate computer= s (UPS backed) shared out via iscsi over a high speed network. It had very successful results. Sounds a bit brave in a production environment to me though