Reconciling files between IBM Spectrum Scale file system and cloud storage tier
This topic describes how to reconcile files migrated between IBM Spectrum Scale™ file systems and the cloud tier.
When you remove files from the file system, no policy is currently available to automatically
remove the cloud objects that are created, which 
results in deleted files or older versions of files that have been
migrated to the cloud to accumulate as
objects on the cloud.
To clean that up, it is recommended to periodically issue the following command to keep the cloud
in sync with the file system so as not to accumulate an excessive
backlog of deletes to be
processed.
mmcloudgateway files reconcile Device {--days-retained DaysRetained}where,
- Device is the device name of the file system that is associated with the node class
- DaysRetained is the number of days for
which the deleted files are to be retained on the cloud.Note: This option provides a control on which files are deleted during the reconcile operation. Only those files that have been deleted for the specified duration are removed from the database. The rest of the files remain in the database. By doing so, files that have been accidentally deleted for the configured duration can be recovered by using the mmcloudgateway files restore option.
If a migrated file is removed from the file system, reconcile removes the corresponding cloud
objects and references that are contained in the cloud directory. Additionally, if multiple versions
of a file are stored on the cloud, reconcile removes all older cloud versions (keeping the most
recent). For example, if a file is migrated, then updated, and migrated again. In this case, two
versions of the file are stored on the cloud. Reconcile removes the older version from the cloud.
Reconcile also deletes cloud objects that are no longer referenced.
Note: Reconcile removes entries
from the cloud directory that references deleted file system objects. Therefore,
it is recommended that any files that need to be restored are restored before you run a reconcile.
It is also recommended to run the reconciliation operation as a background activity during low load
on the IBM
Spectrum Scale cluster.