The xfs filesystem does not support shrinking. This post is mainly about disk replacement and expansion under RAID 10. 1. RAID States and Disk States In mdadm, the RAID states are: clean, normal degraded, still readable and writable, but with reduced fault tolerance reshaping, reorganization in progress, appears during expansion and shrinking resyncing, data synchronization in progress recovering, data recovery in progress, accompanied by degradation as a disk is rebuilt failed In mdadm, the disk states are:

1. Background and Prerequisites Compared with Ext4, Btrfs is a younger file system with more features to play with — snapshots, subvolumes, checksum self-verification, software RAID, and even transparent compression. That said, if you do not have the operations capability behind you, it is best not to use Btrfs. This article records the process of pulling a Btrfs disk out of a Synology DSM system and reading its data.