From mboxrd@z Thu Jan 1 00:00:00 1970 From: Matthew Wilcox Subject: Re: TRIM support in drivers and dm/md? Date: Thu, 4 Nov 2010 07:40:14 -0600 Message-ID: <20101104134014.GB21931@parisc-linux.org> References: <4CD2B2EF.4050005@att.net> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: linux-fsdevel@vger.kernel.org To: Jeff Layton Return-path: Received: from palinux.external.hp.com ([192.25.206.14]:56124 "EHLO mail.parisc-linux.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750782Ab0KDNkP (ORCPT ); Thu, 4 Nov 2010 09:40:15 -0400 Content-Disposition: inline In-Reply-To: <4CD2B2EF.4050005@att.net> Sender: linux-fsdevel-owner@vger.kernel.org List-ID: On Thu, Nov 04, 2010 at 09:19:43AM -0400, Jeff Layton wrote: > Do many of the SATA controllers support TRIM? (i.e. pass > the TRIM command to the SSD). Does anyone know > anything about dm/md supporting TRIM? (I'm thinking LVM > and software RAID tools). As far as I know, there's nothing to be done in any SATA controller driver to support TRIM. It's just up to the drive whether it understands the command. Not sure what the sate of play is with MD/DM and TRIM. It's a bit tricky because some SATA drives will return different garbage from TRIMmed sectors each time they're read. That can hamper a RAID-5/6 rebuild "somewhat". -- Matthew Wilcox Intel Open Source Technology Centre "Bill, look, we understand that you're interested in selling us this operating system, but compare it to ours. We can't possibly take such a retrograde step."