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 9D8C37160D for ; Wed, 8 Jun 2022 17:35:56 +0200 (CEST) Received: from firstgate.proxmox.com (localhost [127.0.0.1]) by firstgate.proxmox.com (Proxmox) with ESMTP id 84FBEAC43 for ; Wed, 8 Jun 2022 17:35:26 +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 6BA65ABDD for ; Wed, 8 Jun 2022 17:35:24 +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 4278D43A6C for ; Wed, 8 Jun 2022 17:35:24 +0200 (CEST) From: Stefan Hrdlicka To: pve-devel@lists.proxmox.com Date: Wed, 8 Jun 2022 17:34:57 +0200 Message-Id: <20220608153457.955356-4-s.hrdlicka@proxmox.com> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20220608153457.955356-1-s.hrdlicka@proxmox.com> References: <20220608153457.955356-1-s.hrdlicka@proxmox.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-SPAM-LEVEL: Spam detection results: 0 AWL 0.127 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 V2 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: Wed, 08 Jun 2022 15:35:56 -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 | 41 ++++++++++++++++++++++++++++++++++++++++- 1 file changed, 40 insertions(+), 1 deletion(-) diff --git a/local-zfs.adoc b/local-zfs.adoc index ab0f6ad..b2d3863 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 +245,44 @@ 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 reserved and used for rebuilding when one drive fails. +This provides, depending on the configuration, faster rebuilding compared to a +RAIDZ in case of drive failure. More information can be found in the official +openZFS documentation. footnote:[OpenZFS dRAID +https://openzfs.github.io/openzfs-docs/Basic%20Concepts/dRAID%20Howto.html] + +NOTE: dRAID is intended for more than 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 + + +Additional information can be found on the manual page: + +---- +# man zpoolconcepts +---- + +Spares and Data +^^^^^^^^^^^^^^^ +The number of `spares` tells the system how many disks it should keep ready in +case of a disk failure. The default value is 0 `spares`. Without spares, +rebuilding won't get any speed benefits. + +`data` defines the number of devices in a redundancy group. The default value is +8. Except when `disks - parity - spares` equal something less than 8, the lower +number is used. In general, a smaller number of `data` devices leads to higher +IOPS, better compression ratios and faster resilvering, but defining fewer data +devices reduces the available storage capacity of the pool. + + Bootloader ~~~~~~~~~~ -- 2.30.2