Documentation Index
Fetch the complete documentation index at: https://docs.xloud.tech/llms.txt
Use this file to discover all available pages before exploring further.
Overview
Preflight assessment runs a set of read-only checks against a discovered workload and returns a compatibility verdict before you submit a migration job. The goal is to catch the issues that would cause a migration to fail or a post-migration boot problem — OS not supported, firmware mismatch, disk layout too complex — while you still have time to fix them on the source.Prerequisites
- A successful discovery scan for the source environment
- Credentials on the registered source with read access to VM configuration and disk metadata
Run Preflight
- Dashboard
- CLI
Select candidate workloads
In Migration → Discover, tick the VMs you plan to migrate and click
Preflight Selected. You can preflight a single VM or an entire wave.
Start the assessment
XMS inspects each VM through the vSphere API and applies the Xloud
compatibility ruleset. The scan is read-only and completes in seconds
for most workloads.
Review the verdict
Each VM receives one of three outcomes:
Expand a row to see every individual check, its status, and the
suggested remediation.
| Verdict | Meaning |
|---|---|
| Pass | All checks passed — safe to migrate |
| Warn | Migration can proceed but with caveats — review the warnings |
| Block | One or more checks failed — resolve before submitting a migration |
All target workloads reach Pass or Warn before you submit a migration.
Check Categories
Preflight runs checks across five categories. Each category produces one or more individual checks that roll up into a category score.Compute
| Check | Description |
|---|---|
| Firmware type | BIOS and UEFI are both supported. Secure Boot state is recorded for post-migration validation. |
| Hardware version | vSphere hardware versions are checked against the supported range for the installed disk transport libraries. |
| Guest OS family | The reported guest OS is matched against the supported Xloud guest catalog. |
| Resource shape | vCPU count and memory are sanity-checked against project quotas in the target Xloud project. |
Storage
| Check | Description |
|---|---|
| Disk count and size | Total disk size is compared to available quota and to the target volume type’s maximum size. |
| Disk layout | Complex layouts (raw device mappings, shared disks, independent disks) are flagged. Standard thin and thick disks are supported. |
| Snapshot state | Active snapshots at migration time may slow down export. XMS flags VMs with long snapshot chains. |
Network
| Check | Description |
|---|---|
| Adapter count | Each source adapter must map to a target Xloud network. |
| Port group names | Port group names are captured for the later network mapping step. |
| MAC preservation | The option to preserve MACs is flagged as informational — a network mapping with conflicting MACs will be rejected at submit time. |
Guest
| Check | Description |
|---|---|
| Driver readiness | The OS is matched against the VirtIO driver set that will be injected during guest conversion. |
| Boot loader | GRUB (Linux) and the Windows BCD are confirmed present. Missing boot loaders are a hard block. |
| Filesystem type | Supported filesystems include ext2/3/4, XFS, Btrfs, NTFS, FAT32, ReFS, and LVM with these underlying types. |
Protection
| Check | Description |
|---|---|
| CBT enabled | Warm migration requires Changed Block Tracking. XMS surfaces this as a warning and offers to enable it in-place. |
| Snapshot support | Warm migration needs the ability to take a snapshot at sync start. Hosts with disabled snapshot support are blocked from warm. |
Common Blockers and Remediation
| Blocker | Root Cause | Fix |
|---|---|---|
| Unsupported guest OS | The guest ID returned by vSphere does not match the Xloud guest catalog | Upgrade or reinstall the guest OS to a supported version before migrating |
| Raw Device Mappings | A disk is mapped directly to a LUN on the source | Convert the RDM to a VMFS-backed disk before migration |
| Shared disks | Two VMs share the same VMDK | Un-share or take an online copy before migration |
| CBT not enabled (warm) | Change tracking has never been turned on | Enable CBT from preflight — XMS will write the config change through the vSphere API |
| Missing boot loader | Damaged GRUB or BCD | Repair the boot loader on the source first; migration cannot recover a broken boot loader |
Preflight vs Runtime Checks
Preflight is a read-only prediction. XMS still performs runtime validation at every stage of the migration pipeline — disk reads, transport negotiation, guest conversion, and volume finalize each have their own checks. A preflight pass does not guarantee a successful migration, but a preflight block does guarantee a migration would fail.Next Steps
Cold Migration
Run a single-pass migration against a powered-off workload
Warm Migration
Start a continuous sync against a running workload
Troubleshooting
Diagnose preflight blockers and discovery errors