Smyg1
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Цитата: Host Managed
The next type of management is known as host managed. With this type of management the host uses commands and Zone information to optimize the behavior of the SMR drive by managing IOs to ensure writes are always sequential within a Zone. If a host sends a non-sequential write within a Zone the drive will reject it and return an error. This gives the drive more predictable performance and would be more likely to be seen initially in enterprise and hyperscale applications.
The down side to host managed is that the SMR drives are not compatible with host systems (HBAs, device drivers, filesystems, databases, etc) that are not SMR aware. That means file systems need to be adapted to support SMR drives. This is occurring, first in the hyperscale space where the largest players in the world have the ability to modify their storage stacks to account for SMR, and now also in the mainstream open source space. The xfs maintainer, Dave Chinner, published a document outlining the SMR optimizations for xfs during the Linux Vault conference in Boston in early March. In the same event, Hannes Rienecke of Suse presented a Zone caching mechanisms that can allow current filesystems to work with host managed SMR drives. It’s likely that these investments together with an appetite for capacity will encourage others to adopt the new open source solutions and pursue modifications to their systems to support SMR drives. |
Цитата: Preparing to use Host-Managed SMR
Ultrastar Archive drives are designed specifically for Active Archive environments and will not work as drop-in replacements for traditional capacity enterprise drives. To take advantage of the capacity and predictable performance of host-managed SMR benefits, customers will need to modify their end application or kernel space to interface with new command sets, and data streams must be sequentialized for writing to the drive. The investments made in software changes will also help enable future host-based SMR solutions, and provide a path to future recording technologies. |
Цитата:| В данных устройствах используется набор расширений к ATA и SCSI для взаимодействия с дисками. Это устройство другого типа (14h), которое требует серьезных изменений во всем Storage Stack и несовместимо с классическими технологиями, то есть без специальной адаптации приложений и операционных систем вы не сможете использовать эти диски. Хост должен выполнять запись на устройства строго последовательно. При этом производительность устройств на 100% предсказуема. Но необходима корректность работы более высокоуровневого ПО для того, чтобы производительность подсистемы хранения была действительно предсказуемой. |
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... его и юартом то назвать язык не поворачивается 
