From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mx1.redhat.com (mx1.redhat.com [172.16.48.31]) by int-mx1.corp.redhat.com (8.13.1/8.13.1) with ESMTP id l1KG0Zc8032729 for ; Tue, 20 Feb 2007 11:00:35 -0500 Received: from ciao.gmane.org (main.gmane.org [80.91.229.2]) by mx1.redhat.com (8.13.1/8.13.1) with ESMTP id l1KG0Wg4004241 for ; Tue, 20 Feb 2007 11:00:33 -0500 Received: from list by ciao.gmane.org with local (Exim 4.43) id 1HJXPk-0007Fe-Rk for linux-lvm@redhat.com; Tue, 20 Feb 2007 17:00:24 +0100 Received: from 203.187.253.248 ([203.187.253.248]) by main.gmane.org with esmtp (Gmexim 0.1 (Debian)) id 1AlnuQ-0007hv-00 for ; Tue, 20 Feb 2007 17:00:24 +0100 Received: from rrs by 203.187.253.248 with local (Gmexim 0.1 (Debian)) id 1AlnuQ-0007hv-00 for ; Tue, 20 Feb 2007 17:00:24 +0100 From: Ritesh Raj Sarraf Date: Tue, 20 Feb 2007 20:19:58 +0530 Message-ID: References: <3nmja4-jtv.ln1@www.researchut.com> <20070220061150.GA3215@percy.comedia.it> <186ra4-8hp.ln1@www.researchut.com> <20070220131909.GA26642@percy.comedia.it> Mime-Version: 1.0 Content-Transfer-Encoding: 7Bit Sender: news Subject: [linux-lvm] Re: Re: LVM + Multipathing Reply-To: LVM general discussion and development List-Id: LVM general discussion and development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , List-Id: Content-Type: text/plain; charset="us-ascii" To: linux-lvm@redhat.com Luca Berra wrote: > i meant that LVM (actually device-mapper) does not do anything special. > it just passes the IO requests from the fs layer to the > underlying block device and if the underlyng block device returns an IO > error then it is passed back to the fs. which will cause ext2 to remount > the filesystem readonly. Hi, Thanks for clarifying. In my case, the block device is hidden by the multipathing layer. It is something like: (Block Device(Multipathing(LVM(Filesystem) ) ) ) Now during takeover/giveback, the multipathing layer is intelligent enough to wait till <120 seconds before declaring that the path has really gone offline and no more paths are available. If within the 120 seconds time span, the takeover succeeds, the path is back online and everything works fine in a non-LVM setup. It is only in an LVM setup that a takeover/giveback ends up with the host OS having a filesystem read-only problem. Now if I go with your explanation, I shouldn't have had the filesystem read-only problem since the I/O is being passed on to the multipathing layer which is intelligent enough to wait for N seconds before really sending an I/O Error. Are there any timeout options in LVM to allow it to wait for N seconds before sending out an error ? (I understand that LVM might not be involved, but just wondering). Thanks, Ritesh -- Ritesh Raj Sarraf RESEARCHUT - http://www.researchut.com "Necessity is the mother of invention." "Stealing logic from one person is plagiarism, stealing from many is research." "The great are those who achieve the impossible, the petty are those who cannot - rrs"