Received: from maia.hub.org (maia-1.hub.org [200.46.208.211]) by mail.postgresql.org (Postfix) with ESMTP id B08B96326F5 for ; Mon, 10 May 2010 16:14:14 -0300 (ADT) Received: from mail.postgresql.org ([200.46.204.86]) by maia.hub.org (mx1.hub.org [200.46.208.211]) (amavisd-maia, port 10024) with ESMTP id 25443-01 for ; Mon, 10 May 2010 19:14:04 +0000 (UTC) X-Greylist: domain auto-whitelisted by SQLgrey-1.7.6 Received: from lo.gmane.org (lo.gmane.org [80.91.229.12]) by mail.postgresql.org (Postfix) with ESMTP id 660DB632BCC for ; Mon, 10 May 2010 16:14:07 -0300 (ADT) Received: from list by lo.gmane.org with local (Exim 4.69) (envelope-from ) id 1OBYQV-0007lq-ET for pgsql-performance@postgresql.org; Mon, 10 May 2010 21:14:03 +0200 Received: from 93-138-219-31.adsl.net.t-com.hr ([93.138.219.31]) by main.gmane.org with esmtp (Gmexim 0.1 (Debian)) id 1AlnuQ-0007hv-00 for ; Mon, 10 May 2010 21:14:03 +0200 Received: from ivoras by 93-138-219-31.adsl.net.t-com.hr with local (Gmexim 0.1 (Debian)) id 1AlnuQ-0007hv-00 for ; Mon, 10 May 2010 21:14:03 +0200 X-Injected-Via-Gmane: http://gmane.org/ To: pgsql-performance@postgresql.org connect(): No such file or directory From: Ivan Voras Subject: Re: 8K recordsize bad on ZFS? Date: Mon, 10 May 2010 21:13:54 +0200 Lines: 17 Message-ID: References: <4BE4ABC9.6040106@agliodbs.com> <4BE852CE.9020802@agliodbs.com> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-Complaints-To: usenet@dough.gmane.org X-Gmane-NNTP-Posting-Host: 93-138-219-31.adsl.net.t-com.hr User-Agent: Mozilla/5.0 (X11; U; FreeBSD amd64; en-US; rv:1.9.1.9) Gecko/20100507 Thunderbird/3.0.4 In-Reply-To: <4BE852CE.9020802@agliodbs.com> X-Virus-Scanned: Maia Mailguard 1.0.1 X-Spam-Status: No, hits=-1.14 tagged_above=-10 required=5 tests=BAYES_00=-1.9, RCVD_IN_SORBS_WEB=0.77, T_RP_MATCHES_RCVD=-0.01 X-Spam-Level: X-Archive-Number: 201005/39 X-Sequence-Number: 38623 On 05/10/10 20:39, Josh Berkus wrote: > On 5/9/10 1:45 AM, Dimitri wrote: >> Josh, >> >> it'll be great if you explain how did you change the records size to >> 128K? - as this size is assigned on the file creation and cannot be >> changed later - I suppose that you made a backup of your data and then >> process a full restore.. is it so? > > You can change the recordsize of the zpool dynamically, then simply copy > the data directory (with PostgreSQL shut down) to a new directory on > that zpool. This assumes that you have enough space on the zpool, of > course. Other things could have influenced your result - 260 MB/s vs 300 MB/s is close enough to be influenced by data position on (some of) the drives. (I'm not saying anything about the original question.)