From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mx1.redhat.com (ext-mx15.extmail.prod.ext.phx2.redhat.com [10.5.110.20]) by int-mx02.intmail.prod.int.phx2.redhat.com (8.13.8/8.13.8) with ESMTP id qB6MPb4B004304 for ; Thu, 6 Dec 2012 17:25:37 -0500 Received: from mail.apocalyptech.com (mail.apocalyptech.com [74.50.51.227]) by mx1.redhat.com (8.14.4/8.14.4) with ESMTP id qB6MPaDR003325 for ; Thu, 6 Dec 2012 17:25:36 -0500 Date: Thu, 6 Dec 2012 16:25:35 -0600 From: CJ Kucera Message-ID: <20121206222535.GA2668@apocalyptech.com> MIME-Version: 1.0 Content-Disposition: inline Subject: [linux-lvm] Questions about issue_discards 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" Content-Transfer-Encoding: 7bit To: linux-lvm@redhat.com Hello, list! I've started to play around with SSD drives and was curious about a couple aspects of the issue_discards configuration option. 1) The lvm.conf comments note that when enabled, it'll still only (obviously) issue discards to storage which happens to support it. Is there a way of querying block devices to find out if they support the feature? 2) Would a change to the issue_discards parameter be picked up automatically by the running kernel? The lvm.conf manpage mentions that it remembers the timestamp of the file "between commands" and will apply changes then, but it almost sounds like that'd be mostly for things like the device scanning list, etc. Thanks! -CJ