Snapshots & Instant Clones
Snapshots and instant clones are at the core of how CiderStack enables fast, safe, and repeatable macOS environments. They allow you to experiment freely, recover instantly, and create multiple ident
Snapshots
A snapshot is a point-in-time capture of a virtual machine’s disk state.
When a snapshot is created, CiderStack records the exact state of the VM at that moment, including:
Installed applications
System configuration
File system contents
macOS version and updates
Snapshots make it possible to return a VM to a known-good state at any time.
Common snapshot use cases
Snapshots are ideal for:
Capturing a clean macOS installation
Saving a pre-MDM enrollment state
Preserving a known-working build environment
Testing software without permanent risk
Rolling back failed updates instantly
You can create as many snapshots as needed for a VM.
How snapshots work
CiderStack snapshots are powered by APFS copy-on-write technology.
This means:
Snapshots are created almost instantly
No full disk copy is performed
Only changed data consumes additional storage
Because APFS tracks changes at the block level, snapshots remain fast even for large disk images.
Restoring a snapshot
Restoring a snapshot reverts the VM’s disk to the exact state captured.
After restoration:
All changes made after the snapshot are discarded
The VM boots exactly as it did when the snapshot was taken
This operation completes in seconds, regardless of disk size.
Instant clones
An instant clone is a new virtual machine created from a snapshot.
Instead of copying the entire disk, CiderStack creates a new VM that shares the snapshot’s data using APFS copy-on-write.
This allows clones to be created almost immediately.
What makes clones instant
Because clones reference the same underlying snapshot:
Creation takes seconds
No large disk duplication occurs
Storage is shared until changes are written
Each clone becomes independent the moment it begins modifying data.
Clone use cases
Instant clones are commonly used for:
CI/CD runner pools
Parallel test environments
Reproducing bugs across identical systems
Spinning up temporary developer machines
Testing macOS betas safely
A single base VM can produce dozens of clones with minimal disk overhead.
Example workflow
A typical workflow might look like:
Create a clean macOS VM
Install required tools (Xcode, SDKs, certificates)
Create a snapshot named
clean-baseCreate instant clones from that snapshot
Destroy clones when finished
The base VM remains untouched and reusable.
Storage efficiency
Snapshots and clones are extremely space-efficient.
Only modified data consumes additional storage.
This enables:
Large VM fleets on limited SSD space
Rapid environment creation
High-density CI runner hosts
Disk usage grows only as changes are introduced.
Snapshot hierarchy
Snapshots form a tree structure:
A snapshot may have multiple child snapshots
Clones may themselves be snapshotted
Restores do not delete snapshot history
This allows advanced workflows such as:
Branching environments
Multi-stage testing pipelines
Versioned VM states
Performance impact
Snapshots and clones have minimal performance overhead.
Because APFS operates at the filesystem layer:
Read performance remains near native speed
Writes occur only for changed blocks
No background copy operations are required
VM performance remains consistent even with many snapshots present.
Best practices
To get the most from snapshots and clones:
Keep a clean base snapshot before major changes
Name snapshots clearly (e.g.
xcode-15-clean)Periodically delete unused snapshots
Use clones for temporary workloads
Avoid installing tools directly on clone VMs you plan to discard
Summary
Snapshot
Point-in-time VM disk state
Restore
Revert VM to snapshot
Instant clone
VM created from snapshot
Storage
Copy-on-write via APFS
Speed
Seconds, regardless of size
Ideal for
CI, testing, experimentation
What’s next
Now that you understand snapshots and clones, you can explore:
Images & Registries
Shared Folders
Networking
Fleet Manager
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