Openzfs set owner5/16/2023 The cache devices are used for extending ZFS's in-memory data cache, which replaces the page cache with the exception of mmap(), which still uses the page cache on most platforms. It will not replace a cache device or log device. The spare devices are used for replacement when a drive fails, provided that the pool's autoreplace property is enabled and your platform supports that functionality. The smallest supported file vdev or disk vdev size is 64MB (2^16 bytes) while the largest depends on the platform, but all platforms should support vdevs of at least 16EB (2^64 bytes). Consequently, the loss of any main top level vdev will result in the loss of the entire pool, such that proper redundancy must be used on all top level vdevs. The use of multiple top level vdevs will affect IOPS in an additive manner where total IOPS will be the sum of the top level vdevs. The commandline tools do not support making mirrors of raidz or raidz of mirrors, although such configurations are used in developer testing. Furthermore, some of these may also have children, such as mirror vdevs and raidz vdevs. file (not recommended for production due to another filesystem adding unnecessary layering)Īny number of these can be children of the root vdev, which are called top-level vdevs.raidz2 (2-disk parity, similar to RAID 6).raidz1 (1-disk parity, similar to RAID 5).Its immediate children can be any vdev type other than itself. At the top level of the tree is the root vdev. The organization of disks in a pool by the SPA is a tree of vdevs or virtual devices. The top layer is the dataset layer, which translates between operations on the filesystems and block devices (zvols) provided by the pool into operations in the DMU. The middle layer is the Data Management Unit, which uses the storage provided by the SPA by reading and writing to it transactionally in an atomic manner. The bottom layer is the Storage Pool Allocator, which handles organizing the physical disks into storage. ZFS itself is composed of three principle layers. At time of import or creation, the pool stores the system's unique hostid and for the purposes of supporting multipath, import into other systems will fail unless forced. At creation, a pool is imported into the system, such that an entry in the zpool.cache file is created. This is because a ZFS pool will always have a mountable filesystem called the root dataset, which is mounted at pool creation. The creation of a usable filesystem with redundancy from a set of disks can be accomplished with 1 command and this will be persistent upon reboots. This allows the same tasks to be accomplished with less code, greater reliability and simplified administration. The ZFS pool is a full storage stack capable of replacing RAID, partitioning, volume management, fstab/exports files and traditional file-systems that span only 1 disk, such as UFS and XFS. The basic unit of storage in ZFS is the pool and from it, we obtain datasets that can be either mountpoints (a mountable filesystem) or block devices. ZFS is a rethinking of the traditional storage stack. 5.3 Platform/Distribution documentation.3.1.4 Drive and/or drive controller hangs.
0 Comments
Leave a Reply. |