mdraid reshape recovery
mdadm reshape changes member count, RAID level, chunk size, or layout while moving data. If it stops, the reshape position separates regions written with the new geometry from regions that may still use the old one.
Understand the symptom
Kernel md metadata can retain new and old values for raid_disks, chunk_size, and layout while reshape_position records progress. Backup-file data may protect a critical stripe window. Recovery maps member roles, events, data offsets, geometry, and boundary state before reconstructing either side of the reshape.
What you may see
Assembly cannot reconcile member events, geometry, or the saved progress position.
Metadata contains both old and new member counts during transition.
One geometry was incorrectly applied across both sides of the reshape boundary.
mdadm needs the external critical-section copy created for the reshape.
Protect the source
A writable start may commit an incorrect member set or geometry.
Old and new layout, role, event, and reshape records can be lost.
The critical window may include the only intact version of moved data.
Do this now
Disable boot assembly, reshape resume, fsck, LVM activation, and application access.
Preserve failed, removed, spare, replacement, and active devices in original slot order.
Capture mdadm --examine, sysfs geometry, reshape position, data offsets, logs, and exact original command.
Preserve any --backup-file and the filesystem or initramfs where it was stored.
NEPFOSYS process
NEPFOSYS reconstructs old and new layout, roles, offsets, events, and reshape boundary.
Images and critical-section backup data are tested without writing to originals.
File systems and priority data are checked across both geometry regions before extraction.
A clear next step
Start a case with the exact symptoms, incident timeline, prior attempts, encryption details, and the files that matter most. NEPFOSYS will route the case to the appropriate DFW intake or nationwide mail-in path.
Start with a case reviewQuestions, answered
It records how far the array has progressed through a geometry-changing reshape.
During reshape, md tracks the geometry already written and the geometry still needed for the remaining region.
That can be unsafe when the protected critical section is needed. Preserve all members and metadata before any restart.
DFW local · Nationwide mail-in