2.8. Understanding storage tiers¶

在 Acronis Cyber Infrastructure 术语中，层是指根据条件组织存储工作负载的磁盘组。例如，可以使用层来分隔由不同租户产生的单独的工作负载。或者，可以有一个快速 SSD 层用于服务或虚拟环境工作负载，一个高容量 HDD 层用于备份存储。

When assigning disks to tiers (which you can do at any time), have in mind that faster storage drives should be assigned to higher tiers. For example, you can use tier 0 for backups and other cold data (CS without SSD cache); tier 1 for virtual environments—a lot of cold data but fast random writes (CS with SSD cache); and tier 2 for hot data (CS on SSD), caches, specific disks, and such.

This recommendation is related to how Acronis Cyber Infrastructure works with storage space. If a storage tier runs out of free space, Acronis Cyber Infrastructure will attempt to temporarily use the space of the lower tiers down to the lowest. If the lowest tier also becomes full, Acronis Cyber Infrastructure will attempt to use a higher one. If you add more storage to the original tier later, the data, temporarily stored elsewhere, will be moved to the tier where it should have been stored originally. For example, if you try to write data to tier 2 and it is full, Acronis Cyber Infrastructure will attempt to write that data to tier 1, then to tier 0. If you add more storage to tier 2 later, the aforementioned data, now stored on the tier 1 or 0, will be moved back to tier 2, where it was meant to be stored originally.

Inter-tier data allocation, as well as the transfer of data to the original tier, occurs in the background. You can disable such migration and keep tiers strict, as described in the Administrator Command Line Guide.