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Defragmentation concept
areas/defragmentation/index.md
areas/defragmentation/defrag_admin/index.md
areas/defragmentation/defrag_admin/defrag_rotation.md
areas/defragmentation/defrag_admin/defrag_shipping.md
concepts/location.md
concepts/container.md
concepts/stock.md
concepts/task.md
concepts/order-outbound.md
concepts/putaway.md
2026-04-10

Defragmentation

Overview

Defragmentation in EasyWMS reorganizes containers in automatic warehouses to optimize the placement of stock, either based on ABC rotation classification or based on upcoming shipping. It is an automatic warehouse-only feature that generates movement tasks to be executed during periods of inactivity, minimizing interference with active operations.

Two types of defragmentation exist:

Type Purpose Criteria
Rotation defragmentation Move containers to their optimal ABC storage zone Item's ABC classification vs. current storage zone
Shipping defragmentation Move containers close to exit in preparation for dispatch Assignment to a shipping order or route

Both types are configured via strategies and can be run manually or automatically via planners.


Rotation Optimization Strategies

Rotation strategies reposition containers to storage zones that match their ABC classification. For example, moving all A-class containers currently stored in zone B to zone A.

Strategy Criteria (Source Selection)

A rotation strategy defines which containers are candidates to be moved:

Criterion Description
ABC classification Required. Containers with this ABC class are candidates
Storage zone Required. The source zone from which to extract candidates
Number of containers Cap on total containers processed by the strategy
Number of references in container Mono-reference only, multi-reference only, or both; for mono-reference: complete/peak/both
Container type Optional filter; if not set, all container types are valid
Location date Only containers placed after a specific date
Assigned containers Whether containers assigned to picking or shipping are candidates
Source aisle Specific automatic aisle to draw from (optional)
Location range X/Y coordinate range within the source aisle
Location sorting Order in which source locations are evaluated (free positions ASC/DESC, X/Y ASC/DESC)

Strategy Rules (Destination Selection)

For each rotation strategy, destination rules specify where to move candidate containers:

Rule Description
Same aisle Move within the same aisle; skip if no valid location in aisle
Specific aisle Move to a designated automatic aisle; skip if no valid location
Storage zones One or more target zones (mandatory — at least one required)
Priority Task priority for defragmentation tasks of this ABC+zone combination

Location search uses putaway strategies in configured sequence order.

Execution

  • Manual: Select strategy in Defragmentation > Rotation optimization strategies → "Apply strategy now"
  • Automatic: Via a defragmentation planner that fires on schedule

Shipping Optimization Strategies

Shipping strategies pre-position containers assigned to upcoming orders near the warehouse exit, speeding up the shipping preparation process.

Strategy Criteria — Shipping (Order / Container Selection)

Criterion Description
Number of orders Cap on orders processed
Assignment type Picking Only / Shipping Only / Picking & Shipping
Order type Routes or Shipping orders
Shipping order type Customer (specific account), Return (specific supplier), Transfer
Order status Creating / Waiting / Released (optionally include Paused)
Destination Orders must have no destination assigned (no packing, stage, or dock)
Sequence number Use container sequence to fill channels in reverse shipping order
Candidate sort Priority: auto-release date ASC, priority ASC, creation date ASC, lines ASC/DESC

If orders don't have all stock assigned yet, the stock assignment process runs first.

Strategy Rules — Shipping (Destination Selection)

Rule Description
Same aisle Move within the same aisle (minimum distance configurable)
Specific aisle Move to a designated automatic aisle
Storage zone One optional target zone (strictly enforced if set)
Location range X/Y coordinate range within the aisle
Location sorting X/Y coordinates ASC/DESC with sequence priority

APS warehouses: EasyWMS finds the optimal channel by capacity and height to guarantee maximum channel occupancy and correct shipping sequence.

Execution (Shipping)

  • Manual: Select strategy in Defragmentation > Shipping optimization strategies → "Apply now"
  • Automatic: Via a defragmentation planner

Defragmentation Planners

Planners enable unattended, scheduled defragmentation. Both rotation and shipping strategies can be scheduled.

Planner Configuration

Field Description
Type Shippings / Rotation / All
Number of executions Run strategies once in the window, or loop until time ends
Active date range Start date (mandatory) + optional end date
Execution time Start time and end time of the defragmentation window
Execution duration How long (hours + minutes) the planner runs
Execution frequency Days of the week (for non-daily planners)

Planner Actions

  • Manual trigger: "Defragment now" button in Defragmentation > Defragmentation planners
  • Automatic: Job runs at scheduled time and applies enabled strategies in sequence
  • Stop: "Stop defragmentation" cancels all pending defragmentation tasks

Operative Details

Rotation Defragmentation Process

  1. EasyWMS identifies containers meeting strategy criteria (not already defragmentation candidates, in locations with automatic unloading aisles)
  2. For APS locations: skips containers with deposit/extraction errors, location locks, or container locks in lower depths
  3. For rack locations: skips on matching-mask errors and locks at any depth
  4. Applies putaway strategies to find valid destination location
  5. Creates movement tasks with configured defragmentation priority
  6. Tasks execute during inactivity periods

Shipping Defragmentation Process

  1. EasyWMS identifies shipping orders/routes meeting criteria (status: Creating/Waiting/Released, no destination assigned)
  2. Applies sort criteria; ties broken by ascending creation date and code
  3. Runs stock assignment for orders without full assignments
  4. Identifies all assigned containers and linked customer containers
  5. Sorts containers in reverse shipping sequence (for sequenced orders) to fill channels optimally
  6. Applies destination rules to find valid locations
  7. Creates movement tasks

Configuration Parameters

Parameter Description Applies to
MAX_DEFRAG_TASKS Max simultaneous defragmentation tasks per automatic aisle Both
MAX_OPTIMIZATION_DEFRAG_CHANNEL Max channels being defragmented simultaneously per aisle; 0 = no limit (only MAX_DEFRAG_TASKS applies) Both
MAX_DEFRAG_ATTEMPT Max attempts to find a valid location for shipping defragmentation; after this, container is no longer a candidate Shipping

Interface

Path Equipment
Defragmentation > Rotation optimization strategies PC
Defragmentation > Shipping optimization strategies PC
Defragmentation > Defragmentation planners PC
Warehouse > Tasks (monitoring defrag tasks) PC

Common Errors

Symptom Cause Solution
No defragmentation tasks generated No valid destination location found Check zone configuration in strategies; verify putaway strategies are defined
Container skipped by rotation strategy Container has lock preventing movement, or is in an error state (APS deposit/extraction error) Resolve location/container locks first
Shipping defragmentation container never moved MAX_DEFRAG_ATTEMPT reached without finding valid location Review shipping strategy destination rules; check zone availability
Defragmentation runs during active operations Planner window overlaps with peak activity Adjust planner execution time to off-peak hours
Tasks not generated for APS location Lower-depth containers block movement Resolve APS channel issues first

  • location — Defragmentation moves containers between locations; rotation strategies use storage zones; only automatic aisles are valid
  • container — Containers are the unit of movement; ABC classification, type, and references-per-container govern candidate selection
  • stock — Stock records follow container movements; STK.MOVE and CON.MOVE transactions generated
  • task — Defragmentation generates movement tasks executed during inactivity; MAX_DEFRAG_TASKS limits concurrency
  • order-outbound — Shipping defragmentation is triggered by outbound orders; status must be Creating/Waiting/Released
  • putaway — Rotation defragmentation uses putaway strategies to find destination locations