From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: util-linux-owner@vger.kernel.org Received: from mail-qw0-f46.google.com ([209.85.216.46]:46604 "EHLO mail-qw0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751985Ab1FLTDB (ORCPT ); Sun, 12 Jun 2011 15:03:01 -0400 Received: by qwk3 with SMTP id 3so1927488qwk.19 for ; Sun, 12 Jun 2011 12:03:00 -0700 (PDT) Message-ID: <4DF50D58.9020800@tds.net> Date: Sun, 12 Jun 2011 15:02:48 -0400 From: John Lindgren MIME-Version: 1.0 To: util-linux@vger.kernel.org Subject: blkid: excessive random reads probing for ZFS on NTFS filesystem Content-Type: text/plain; charset=UTF-8 Sender: util-linux-owner@vger.kernel.org List-ID: Hi, 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. 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? -- John Lindgren