From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: util-linux-owner@vger.kernel.org Received: from mx1.redhat.com ([209.132.183.28]:62524 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751139Ab1FTLQo (ORCPT ); Mon, 20 Jun 2011 07:16:44 -0400 Date: Mon, 20 Jun 2011 13:16:40 +0200 From: Karel Zak To: John Lindgren Cc: util-linux@vger.kernel.org, Andreas Dilger Subject: Re: blkid: excessive random reads probing for ZFS on NTFS filesystem Message-ID: <20110620111640.GE17967@nb.net.home> References: <4DF50D58.9020800@tds.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii In-Reply-To: <4DF50D58.9020800@tds.net> Sender: util-linux-owner@vger.kernel.org List-ID: On Sun, Jun 12, 2011 at 03:02:48PM -0400, John Lindgren wrote: > I noticed blkid causing a noticeable amount of disk hits while > identifying an NTFS (Win7) partition, and did an strace to find out why > this was. It seems that the probe_zfs() function does a > seek-and-read-41-bytes pattern 64 times in the 130 to 520 KB region of > the partition. Is it really so big problem on traditional HDDs? > This of course is slow on a traditional hard disk, and > seems excessive. I don't know the internals of NTFS or of ZFS. Can > someone with a little more knowledge in this area provide some pointers > as to why this might be happening? CC: Andreas who is the code (co)author. Karel -- Karel Zak http://karelzak.blogspot.com