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 1909974FAE for ; Thu, 2 Jun 2022 13:23:39 +0200 (CEST) Received: from firstgate.proxmox.com (localhost [127.0.0.1]) by firstgate.proxmox.com (Proxmox) with ESMTP id BFF8D3680 for ; Thu, 2 Jun 2022 13:23:08 +0200 (CEST) Received: from proxmox-new.maurer-it.com (proxmox-new.maurer-it.com [94.136.29.106]) (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 6A4BF3634 for ; Thu, 2 Jun 2022 13:23:07 +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 37E6B42BD9 for ; Thu, 2 Jun 2022 13:23:01 +0200 (CEST) From: Stefan Hrdlicka To: pve-devel@lists.proxmox.com Date: Thu, 2 Jun 2022 13:22:34 +0200 Message-Id: <20220602112234.1868726-4-s.hrdlicka@proxmox.com> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20220602112234.1868726-1-s.hrdlicka@proxmox.com> References: <20220602112234.1868726-1-s.hrdlicka@proxmox.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-SPAM-LEVEL: Spam detection results: 0 AWL 0.345 Adjusted score from AWL reputation of From: address BAYES_00 -1.9 Bayes spam probability is 0 to 1% KAM_DMARC_STATUS 0.01 Test Rule for DKIM or SPF Failure with Strict Alignment SPF_HELO_NONE 0.001 SPF: HELO does not publish an SPF Record SPF_PASS -0.001 SPF: sender matches SPF record T_SCC_BODY_TEXT_LINE -0.01 - URIBL_BLOCKED 0.001 ADMINISTRATOR NOTICE: The query to URIBL was blocked. See http://wiki.apache.org/spamassassin/DnsBlocklists#dnsbl-block for more information. [github.io] Subject: [pve-devel] [PATCH pve-docs 3/3] fix #3967: add ZFS dRAID documentation 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: Thu, 02 Jun 2022 11:23:39 -0000 add some basic explanation how ZFS dRAID works including links to openZFS for more details add documentation for two dRAID parameters used in code Signed-off-by: Stefan Hrdlicka --- local-zfs.adoc | 40 +++++++++++++++++++++++++++++++++++++++- 1 file changed, 39 insertions(+), 1 deletion(-) diff --git a/local-zfs.adoc b/local-zfs.adoc index ab0f6ad..8eb681c 100644 --- a/local-zfs.adoc +++ b/local-zfs.adoc @@ -32,7 +32,8 @@ management. * Copy-on-write clone -* Various raid levels: RAID0, RAID1, RAID10, RAIDZ-1, RAIDZ-2 and RAIDZ-3 +* Various raid levels: RAID0, RAID1, RAID10, RAIDZ-1, RAIDZ-2, RAIDZ-3, +dRAID, dRAID2, dRAID3 * Can use SSD for cache @@ -244,6 +245,43 @@ them, unless your environment has specific needs and characteristics where RAIDZ performance characteristics are acceptable. +ZFS dRAID +~~~~~~~~~ + +In a ZFS dRAID (declustered RAID) the hot spare drive(s) participate in the RAID. +Their spare capacity is reservered and used for rebuilding when one drive fails. +This provides depending on the configuration faster rebuilding compaired to a +RAIDZ in case of drive failure. More information can be found in the official +openZFS documenation. footnote:[OpenZFS dRAID +https://openzfs.github.io/openzfs-docs/Basic%20Concepts/dRAID%20Howto.html] + +NOTE: dRAID is intended for more then 10-15 disks in a dRAID. A RAIDZ +setup should be better for a lower amount of disks in most use cases. + + * `dRAID1` or `dRAID`: requires at least 2 disks, one can fail before data is +lost + * `dRAID2`: requires at least 3 disks, two can fail before data is lost + * `dRAID3`: requires at least 4 disks, three can fail before data is lost + + +Additonal information can be found on manual page: + +---- +# man zpoolconcepts +---- + +spares and data +^^^^^^^^^^^^^^^ +The number of `spares` tells the system how many disks it should keep ready in +case of of a disk failure. The default value is 0 `spares`. Without spares +rebuilding won't get any speed benefits. + +The number of `data` devices specifies the size of a parity group. The default +is 8 if the number of `disks - parity - spares >= 8`. A higher number of `data` +and parity drives increases the allocation size (e.g. for 4k sectors with +default `data`=6 minimum allocation size is 24k) which can affect compression. + + Bootloader ~~~~~~~~~~ -- 2.30.2