In addition to standard monitoring on a per-share basis, it's also possible to
monitor shadow migration system-wide through Analytics in Oracle ZFS Storage Appliance Analytics Guide
. The shadow migration analytics are
available under the "Data Movement" category. There are two basic statistics
Shadow Migration Requests
This statistic tracks requests for files or directories that are not cached
and known to be local to the filesystem. It does account for both migrated and
unmigrated files and directories, and can be used to track the latency incurred
as part of shadow migration, as well as track the progress of background
migration. It can be broken down by file, share, project, or latency. It
currently encompasses both synchronous and asynchronous (background) migration,
so it's not possible to view only latency visible to clients.
Shadow Migration Bytes
This statistic tracks bytes transferred as part of migrating file or directory
contents. This does not apply to metadata (extended attributes, ACLs, etc). It
gives a rough approximation of the data transferred, but source datasets with a
large amount of metadata will show a disproportionally small bandwidth. The
complete bandwidth can be observed by looking at network analytics. This
statistic can be broken down by local filename, share, or project.
Shadow migration operations
This statistic tracks operations that require going to the source filesystem.
This can be used to track the latency of requests from the shadow migration
source. It can be broken down by file, share, project, or latency.