From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from firstgate.proxmox.com (firstgate.proxmox.com [212.224.123.68]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits)) (No client certificate requested) by lists.proxmox.com (Postfix) with ESMTPS id 8B49E6CE0E for ; Wed, 31 Mar 2021 11:52:32 +0200 (CEST) Received: from firstgate.proxmox.com (localhost [127.0.0.1]) by firstgate.proxmox.com (Proxmox) with ESMTP id 7FA7AD6DD for ; Wed, 31 Mar 2021 11:52:32 +0200 (CEST) Received: from proxmox-new.maurer-it.com (proxmox-new.maurer-it.com [212.186.127.180]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits)) (No client certificate requested) by firstgate.proxmox.com (Proxmox) with ESMTPS id 8B50DD6D4 for ; Wed, 31 Mar 2021 11:52:31 +0200 (CEST) Received: from proxmox-new.maurer-it.com (localhost.localdomain [127.0.0.1]) by proxmox-new.maurer-it.com (Proxmox) with ESMTP id 52A9045882 for ; Wed, 31 Mar 2021 11:52:31 +0200 (CEST) From: Stoiko Ivanov To: pve-devel@lists.proxmox.com Date: Wed, 31 Mar 2021 11:52:04 +0200 Message-Id: <20210331095204.23831-1-s.ivanov@proxmox.com> X-Mailer: git-send-email 2.20.1 MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-SPAM-LEVEL: Spam detection results: 0 AWL 0.060 Adjusted score from AWL reputation of From: address KAM_DMARC_STATUS 0.01 Test Rule for DKIM or SPF Failure with Strict Alignment RCVD_IN_DNSWL_MED -2.3 Sender listed at https://www.dnswl.org/, medium trust SPF_HELO_NONE 0.001 SPF: HELO does not publish an SPF Record SPF_PASS -0.001 SPF: sender matches SPF record Subject: [pve-devel] [PATCH docs v2] zfs: add section on zpool-features X-BeenThere: pve-devel@lists.proxmox.com X-Mailman-Version: 2.1.29 Precedence: list List-Id: Proxmox VE development discussion List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 31 Mar 2021 09:52:32 -0000 primarily in order to warn users booting from ZFS with grub. Signed-off-by: Stoiko Ivanov Reviewed-By: Aaron Lauterer --- * incorporated Dylan's excellent and almost sed'able feedback * added Aaron's Reviewed-By tag despite sending a v2, since the content did not change - hope that's ok local-zfs.adoc | 35 +++++++++++++++++++++++++++++++++++ 1 file changed, 35 insertions(+) diff --git a/local-zfs.adoc b/local-zfs.adoc index 4819678..2b6042f 100644 --- a/local-zfs.adoc +++ b/local-zfs.adoc @@ -699,3 +699,38 @@ in the pool will opt in for small file blocks). ---- # zfs set special_small_blocks=0 / ---- + +[[sysadmin_zfs_features]] +ZFS Pool Features +~~~~~~~~~~~~~~~~~ + +Changes to the on-disk format in ZFS are only made between major version changes +and are specified through *features*. All features, as well as the general +mechanism are well documented in the `zpool-features(5)` manpage. + +Since enabling new features can render a pool not importable by an older version +of ZFS, this needs to be done actively by the administrator, by running +`zpool upgrade` on the pool (see the `zpool-upgrade(8)` manpage). + +Unless you need to use one of the new features, there is no upside to enabling +them. + +In fact, there are some downsides to enabling new features: + +* A system with root on ZFS, that still boots using `grub` will become + unbootable if a new feature is active on the rpool, due to the incompatible + implementation of ZFS in grub. +* The system will not be able to boot with an older kernel, which still ships + with the old ZFS modules. +* Booting an older {pve} ISO to repair a non-booting system will likewise not + work. + +IMPORTANT: Do not upgrade your rpool if your system is still booted with `grub`, +as this will render your system unbootable. This includes systems installed +before {pve} 5.4, and systems booting with legacy BIOS boot (see +xref:sysboot_determine_bootloader_used[how to determine the bootloader]). + +.Enable new features for a pool: +---- +# zpool upgrade +---- -- 2.20.1