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=-3.5 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,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 71659C388F9 for ; Sat, 31 Oct 2020 00:28:08 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id CB591206E5 for ; Sat, 31 Oct 2020 00:28:07 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=dirtcellar.net header.i=@dirtcellar.net header.b="Iv2m7Td8" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1725998AbgJaA2D (ORCPT ); Fri, 30 Oct 2020 20:28:03 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:43342 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726099AbgJaA2B (ORCPT ); Fri, 30 Oct 2020 20:28:01 -0400 Received: from smtp.domeneshop.no (smtp.domeneshop.no [IPv6:2a01:5b40:0:3005::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 38C67C0613D5 for ; Fri, 30 Oct 2020 17:28:00 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=dirtcellar.net; s=ds201912; h=Content-Transfer-Encoding:Content-Type: MIME-Version:Date:Message-ID:Subject:From:To:Reply-To:Sender:Cc:Content-ID: Content-Description:Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc :Resent-Message-ID:In-Reply-To:References:List-Id:List-Help:List-Unsubscribe: List-Subscribe:List-Post:List-Owner:List-Archive; bh=HpOVGxJDRbP2Rz1i1DFFog+YxfgS78XizC3e07j+EKk=; b=Iv2m7Td8LFN8IlWTqXiotIAchc jhJNr+0DD9GhZqFwHlaMEEufH+4qu3g5WYNe9yBxUXYv2O4lRoeeAeT97CfWRv3zD/Ah9n96IL8sQ 6Fwt8qS8iyAdb4+UqIEextzmV6RSjEIq4oAtItf26EBEHPjXdhimzJW0l9AsbOjmphnkRmTIuCTnz 0GqAQgnBq6DQIAj7SMge4aEZKMOn6tlv47fx1uf56iMEAq/LLXB8L4DkIezaEfLi3WDDrYM4gOVUa IL4kvxg6jybkg56UPpOU0tn+4Y/AnRrcCSwz8i95N10yrW50Im6jI0fvqbplpx1oGXwdqiahbttc3 bdfs2qwg==; Received: from 254.79-160-170.customer.lyse.net ([79.160.170.254]:47475 helo=[10.0.0.10]) by smtp.domeneshop.no with esmtpsa (TLS1.3:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.92) (envelope-from ) id 1kYekP-0000UO-Ia for linux-btrfs@vger.kernel.org; Sat, 31 Oct 2020 01:27:57 +0100 Reply-To: waxhead@dirtcellar.net To: Btrfs BTRFS From: waxhead Subject: Switching from spacecache v1 to v2 Message-ID: Date: Sat, 31 Oct 2020 01:27:57 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Firefox/60.0 SeaMonkey/2.53.4 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-btrfs@vger.kernel.org A couple of months ago I asked on IRC how to properly switch from version 1 to version 2 of the space cache. I also asked if the space cache v2 was considered stable. I only remember what we talked about, and from what I understood it was not as easy to switch as the wiki may seem to indicate. We run a box with a btrfs filesystem at 19TB, 9 disks, 11 subvolumes that contains about 6.5 million files (and this number is growing). The filesystem has always been mounted with just the default options. Performance is slow, and it improved when I moved the bulk of the files to various subvolumes for some reason. The wiki states that performance on very large filesystems (what is considered large?) may degrade drastically. I would like to try v2 of the space cache to see if that improves speed a bit. So is space cache v2 safe to use?! And How do I make the switch properly?