Monitoring Migration Progress

To monitor shadow migration progress, Oracle ZFS Storage Appliance provides such statistics as:

• Size of data transferred so far

• Estimate of remaining size to be migrated

• Migration time so far

• Migration time remaining

• Migration errors

At the beginning of migration, the appliance obtains the source filesystem statistics and calculates its size. It uses these values to provide a reasonably accurate visual representation of migration progress and an estimation of the remaining data to be migrated. Of note, the remaining bytes is an estimate based on the assumption that an entire filesystem is being migrated. If only part of the source file system is migrated, the remaining bytes estimate is inaccurate. If the source filesystem has nested filesystems, the total filesystem size is recalculated when the nested mount point is discovered during migration, and the remaining bytes are re-estimated based on the newly calculated total. Estimation of remaining bytes may be inaccurate if the source filesystem uses compression. These values are available in the BUI and CLI through both the standard filesystem properties as well as properties of the shadow migration node (or UI panel).

Note:

When a sparse file (a file with empty blocks) is migrated, the target file will be smaller than the source file size. Shadow migration does not write the empty blocks to the target file, resulting in less space usage.

The following tasks describe how to monitor shadow migration progress and view any resulting errors. To view shadow migration errors using the RESTful API, see Filesystem Operations in Oracle ZFS Storage Appliance RESTful API Guide, Release OS8.8.x.