From mboxrd@z Thu Jan 1 00:00:00 1970 From: Tomasz Chmielewski Subject: Re: can I freeze I/O for some time to a given disk / md / dm device? Date: Tue, 16 Dec 2008 17:19:21 +0100 Message-ID: <4947D509.6080005@wpkg.org> References: <49479897.1080500@wpkg.org> <20081216161312.GI18423@boogie.lpds.sztaki.hu> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20081216161312.GI18423@boogie.lpds.sztaki.hu> Sender: linux-raid-owner@vger.kernel.org To: Gabor Gombas Cc: Linux IDE , Linux-Raid , LVM general discussion and development List-Id: linux-ide@vger.kernel.org Gabor Gombas schrieb: > On Tue, Dec 16, 2008 at 01:01:27PM +0100, Tomasz Chmielewski wrote: > >> Is it possible to "freeze I/O" for some time to a given disk / md / dm >> device? >> >> Say, "freeze I/O" so that userspace waits for any response for 30, 60 >> seconds or more? > > For real disks you can use /sys/block/sdX/device/unload_heads to achieve > something similar (see Documentation/laptops/disk-shock-protection.txt > in the kernel source about how to use it). That won't work for md/dm > devices though. Thanks, I think I have enough hints now. Bryn M. Reeves on linux-lvm list suggested using dmsetup's suspend/resume, which seems to be the easiest way for this purpose (requires device mapper / LVM). -- Tomasz Chmielewski http://wpkg.org 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 mBGGKGXX000331 for ; Tue, 16 Dec 2008 11:20:16 -0500 Received: from mx03.syneticon.net (mx03.syneticon.net [87.79.32.166]) by mx1.redhat.com (8.13.8/8.13.8) with ESMTP id mBGGJRMw021931 for ; Tue, 16 Dec 2008 11:19:28 -0500 Message-ID: <4947D509.6080005@wpkg.org> Date: Tue, 16 Dec 2008 17:19:21 +0100 From: Tomasz Chmielewski MIME-Version: 1.0 References: <49479897.1080500@wpkg.org> <20081216161312.GI18423@boogie.lpds.sztaki.hu> In-Reply-To: <20081216161312.GI18423@boogie.lpds.sztaki.hu> Content-Transfer-Encoding: 7bit Subject: [linux-lvm] Re: can I freeze I/O for some time to a given disk / md / dm device? 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"; format="flowed" To: Gabor Gombas Cc: Linux-Raid , Linux IDE , LVM general discussion and development Gabor Gombas schrieb: > On Tue, Dec 16, 2008 at 01:01:27PM +0100, Tomasz Chmielewski wrote: > >> Is it possible to "freeze I/O" for some time to a given disk / md / dm >> device? >> >> Say, "freeze I/O" so that userspace waits for any response for 30, 60 >> seconds or more? > > For real disks you can use /sys/block/sdX/device/unload_heads to achieve > something similar (see Documentation/laptops/disk-shock-protection.txt > in the kernel source about how to use it). That won't work for md/dm > devices though. Thanks, I think I have enough hints now. Bryn M. Reeves on linux-lvm list suggested using dmsetup's suspend/resume, which seems to be the easiest way for this purpose (requires device mapper / LVM). -- Tomasz Chmielewski http://wpkg.org