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 X-Spam-Level: X-Spam-Status: No, score=-0.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id EFB24C43331 for ; Tue, 31 Mar 2020 17:42:32 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id C238920BED for ; Tue, 31 Mar 2020 17:42:32 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726150AbgCaRmc (ORCPT ); Tue, 31 Mar 2020 13:42:32 -0400 Received: from len.romanrm.net ([91.121.86.59]:34412 "EHLO len.romanrm.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725976AbgCaRmb (ORCPT ); Tue, 31 Mar 2020 13:42:31 -0400 Received: from natsu (natsu.40.romanrm.net [IPv6:fd39:aa:c499:6515:e99e:8f1b:cfc9:ccb8]) by len.romanrm.net (Postfix) with SMTP id CBB8640044; Tue, 31 Mar 2020 17:42:29 +0000 (UTC) Date: Tue, 31 Mar 2020 22:42:29 +0500 From: Roman Mamedov To: Eli V Cc: Paul Jones , Andrei Borzenkov , Victor Hooi , linux-btrfs Subject: Re: Using Intel Optane to accelerate a BTRFS array? (equivalent of ZLOG/SIL for ZFS?) Message-ID: <20200331224229.1c216ab2@natsu> In-Reply-To: References: <20200331221749.52b10248@natsu> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-btrfs-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-btrfs@vger.kernel.org On Tue, 31 Mar 2020 13:31:19 -0400 Eli V wrote: > Yes using lvm cache is an option, and will give you actual caching of > the data files as well. However, in my experience it doesn't do much > caching of metadata so using it on large filesystems doesn't seem to > improve interactive usage much at all, i.e. ls -l, or btrfs filesystem > usage etc. Forgot to mention that in my case (on a large media server) I had great results with the described setup, especially noticeable in the mount time. Walking large directories in a GUI file manager was more responsive too. Not to mention mass deletion of snapshots. LVM cache seemed to know well to avoid polluting itself with infrequently accessed sequential-pattern bulk operations (i.e. copying or reading back the actual file data) and appeared to cache mostly the metadata as it should. For anyone considering this, give it a try, and give it at least a few days of normal usage to properly warm up. -- With respect, Roman