From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id D5D14C4332F for ; Mon, 28 Nov 2022 01:26:34 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229717AbiK1B0e (ORCPT ); Sun, 27 Nov 2022 20:26:34 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:44206 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229695AbiK1B0c (ORCPT ); Sun, 27 Nov 2022 20:26:32 -0500 Received: from mail.thelounge.net (mail.thelounge.net [91.118.73.15]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id A40C833A for ; Sun, 27 Nov 2022 17:26:30 -0800 (PST) Received: from [10.10.10.2] (rh.vpn.thelounge.net [10.10.10.2]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (P-256)) (No client certificate requested) (Authenticated sender: h.reindl@thelounge.net) by mail.thelounge.net (THELOUNGE MTA) with ESMTPSA id 4NL7903n3nzXLf; Mon, 28 Nov 2022 02:26:28 +0100 (CET) Message-ID: Date: Mon, 28 Nov 2022 02:26:28 +0100 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101 Thunderbird/102.5.0 Subject: Re: how do i fix these RAID5 arrays? Content-Language: en-US To: Wol , Roman Mamedov Cc: John Stoffel , David T-G , Linux RAID list References: <20221123220736.GD19721@jpo> <20221124032821.628cd042@nvm> <20221124211019.GE19721@jpo> <25474.28874.952381.412636@quad.stoffel.home> <62b72b4e-8461-e616-1227-4dcef8853143@youngman.org.uk> <7316d29a-bab6-b8a2-5c77-803af8de378b@thelounge.net> <20221127230828.3cfe728b@nvm> <2c013c78-99ca-df05-117a-2f58b237b595@youngman.org.uk> From: Reindl Harald Organization: the lounge interactive design In-Reply-To: <2c013c78-99ca-df05-117a-2f58b237b595@youngman.org.uk> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-raid@vger.kernel.org Am 27.11.22 um 20:21 schrieb Wol: > On 27/11/2022 18:08, Roman Mamedov wrote: >> On Sun, 27 Nov 2022 14:33:37 +0000 >> Wol wrote: >> >>> If raid supports trim, that means it intercepts the trim commands, and >>> uses it to keep track of what's being used by the layer above. >>> >>> In other words, if the filesystem is only using 10% of the disk, >>> supporting trim means that raid knows which 10% is being used and only >>> bothers syncing that! >> >> Not sure which RAID system you are speaking of, but that's not presently >> implemented in mdadm RAID. It does not use TRIM of the array to keep >> track of >> unused areas on the underlying devices, to skip those during rebuilds. >> And I >> am unaware of any other RAID that does. Would be nice to have though. >> > Yup that's what I was saying - it would very much be a "nice to have" you clearly need to distinct "nice to have" vesus "state of play" - nobody gain anything from nice to have when the topic are *existing* differences what is "nice to have" for mdadm is "exists in ZFS/BTRFS"