ついでだからこっちも貼っておく。WDは例の赤SMRについて弁明というか
解説している。特に気になったのは、RAIDで赤SMRの件、社内テストでは
問題なし。と断言している点。論社は懐疑的な評価スタンスだけども。
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Western Digital statement

Shingled magnetic recording (SMR) is a hard drive technology that efficiently
increases areal density and capacity for users managing increasing amounts of data,
thus lowering users’ TCO. There are both device-managed and host-managed types,
each for different use cases.

All our WD Red drives are designed to meet or exceed the performance requirements
and specifications for common and intended small business/home NAS workloads.
WD Red capacities 2TB-6TB currently employ device-managed shingled magnetic
recording (DMSMR) to maximize areal density and capacity. WD Red 8-14TB drives
use conventional magnetic recording (CMR). DMSMR should not be confused with
host-managed SMR (HMSMR), which is designed for data center applications having
respective workload requirements and host integration.

DMSMR is designed to manage intelligent data placement within the drive, rather
than relying on the host, thus enabling a seamless integration for end users.
The data intensity of typical small business/home NAS workloads is intermittent,
leaving sufficient idle time for DMSMR drives to perform background data
management tasks as needed and continue an optimal performance experience for users.

WD Red drives are designed and tested for an annualized workload rate up to 180TB.
Western Digital has seen reports of WD Red use in workloads far exceeding our specs
and recommendations. Should users’ use cases exceed intended workloads,
we recommend WD Red Pro or Ultrastar data center drives.