From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1759416Ab3BXBVG (ORCPT ); Sat, 23 Feb 2013 20:21:06 -0500 Received: from li9-11.members.linode.com ([67.18.176.11]:49618 "EHLO imap.thunk.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1758968Ab3BXBVF (ORCPT ); Sat, 23 Feb 2013 20:21:05 -0500 Date: Sat, 23 Feb 2013 20:20:52 -0500 From: "Theodore Ts'o" To: Dave Chinner Cc: Marcus Sundman , Jan Kara , linux-kernel@vger.kernel.org Subject: Re: Debugging system freezes on filesystem writes Message-ID: <20130224012052.GC1196@thunk.org> Mail-Followup-To: Theodore Ts'o , Dave Chinner , Marcus Sundman , Jan Kara , linux-kernel@vger.kernel.org References: <20121113135159.GA18651@quack.suse.cz> <50A592BA.8050709@hibox.fi> <20121121233021.GA8730@quack.suse.cz> <50B4E6F2.6010000@hibox.fi> <20121205153216.GF5706@quack.suse.cz> <51248C5F.4040606@hibox.fi> <5124B613.6040400@hibox.fi> <20130222205144.GA30600@quack.suse.cz> <5127FEEA.60207@hibox.fi> <20130224001222.GB5551@dastard> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20130224001222.GB5551@dastard> User-Agent: Mutt/1.5.21 (2010-09-15) X-SA-Exim-Connect-IP: X-SA-Exim-Mail-From: tytso@thunk.org X-SA-Exim-Scanned: No (on imap.thunk.org); SAEximRunCond expanded to false Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sun, Feb 24, 2013 at 11:12:22AM +1100, Dave Chinner wrote: > > >/dev/sda6 /home ext4 rw,noatime,discard 0 0 > ^^^^^^^ > I'd say that's your problem.... Looks like the Sandisk U100 is a good SSD for me to put on my personal "avoid" list: http://thessdreview.com/our-reviews/asus-zenbook-ssd-review-not-necessarily-sandforce-driven-shows-significant-speed-bump/ There are a number of SSD's which do not implement "trim" efficiently, so these days, the recommended way to use trim is to run the "fstrim" command out of crontab. There are some high performance flash devices (especially PCIe attached flash devices, where the TRIM command doesn't necessarily mean waiting for the entire contents of the Native Command Queue to drain) where using the discard mount option makes sense for best performance, but for most SATA drives (especially the really cheap-sh*t ones), I don't recommend it. If it weren't for the fact that for these devices exist and the discard option is especially useful for them, I probably would have removed the discard option from ext4. - Ted