PowerScale OneFS 9.2.1.0 CloudPools Administration Guide

Overview of CloudPools file processing

CloudPools archives file data to the cloud. You can access the archived data whenever needed, for reading or writing. You can also fully recall the data from the cloud, essentially reversing the archive.

File pool policies

You create file pool policies to identify the files to archive to the cloud. When a file pool policy that contains cloud actions runs, CloudPools moves file data to the cloud. The data is stored in specialized cloud data objects, collectively called cloud data. File data can be encrypted and compressed before it is archived to the cloud.

For general information about how file pool policies run and the resulting policy jobs, see the OneFS Administration Guide.

SmartLink files

For each file that is archived, CloudPools retains a local proxy file. The proxy is called a SmartLink file. SmartLink files include special metadata and maps to the file data in the cloud.

Inline access

When a user browses OneFS, typically through an SMB connection or NFS export, SmartLink files appear in place of the datafiles. When a user opens a SmartLink file, CloudPools manages the data access. This process is called inline access. A read request retrieves data from the cloud and caches it locally. For subsequent reads, if the requested data is not yet cached locally, it is retrieved at that time. A write to an uncached area causes a read of a block of data from the cloud. The data is cached and then modified.

As the user views the file, CloudPools continues to cache data as required by the application. If the user modifies and saves the file, the changes are also held in cache. Periodically, CloudPools scans SmartLink files for pending data changes and writes them to the appropriate objects in the cloud. In this way, the archived data is kept up to date.

Recall

You can recall archived files from the cloud. CloudPools fully replaces the SmartLink files with the recalled files.

File pool policies and SmartLink files

Like any file in OneFS, SmartLink files are controlled either by the default file pool policy or by parameters in a custom file pool policy. If you configure additional file pool policies, these policies have priority over the default file pool policy.

File pool policies contain instructions that determine how OneFS manages files across a cluster and in the cloud.

Because SmartLink files produced by CloudPools are retained on the cluster, OneFS applies file pool policies to these files, as well.

When file pool policies run, the system compares each file on the system with each file pool policy. A file can match only some aspects of a custom file pool policy (for example, SSD strategy and snapshot configuration). In that case, the custom file pool policy controls the matching aspects, and the default file pool policy controls all other aspects of file handling.