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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.

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Overview

Block device mapping controls how storage is attached to an instance at launch time. The Dashboard’s Instance Create wizard provides a visual interface for configuring the system disk, additional data disks, and CD-ROM devices. Understanding these options helps you choose the right storage configuration for your workloads.
Prerequisites
  • Block storage service enabled on the platform
  • Available volume types configured by your administrator
  • Sufficient volume and storage quota

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Storage Options in the Create Wizard

The Step 1 (Base Config) of the Instance Create wizard provides these storage configuration options:

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Boot Source and System Disk

SourceBoot From VolumeResult
ImageYes (default)Creates a new persistent system disk from the image
ImageNoBoots directly from image (ephemeral root disk — lost on delete)
Instance SnapshotAutomaticSystem disk configuration inherited from snapshot
Bootable VolumeN/ABoots from existing volume (count limited to 1)
Instances booted without a persistent volume (Boot From Volume = No) lose their root disk when deleted. Always use boot-from-volume for production workloads that need data persistence.

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System Disk Configuration

When Boot From Volume is set to Yes, configure the system disk:
FieldDescription
Volume TypeSelect from available storage backends (e.g., SSD, HDD tiers)
Size (GiB)Minimum is the largest of: flavor disk size, image minimum disk, and image size
Delete on TerminationWhether to delete the boot volume when the instance is deleted

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Data Disks

Click Add Data Disks to attach additional persistent volumes at launch. Each data disk has the same configuration options as the system disk (Volume Type, Size, Delete on Termination).
Limit the number of attached disks to 16 or fewer for optimal I/O performance. The dashboard shows a recommendation when adding data disks.

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CD-ROM Device

The wizard supports attaching a CD-ROM device at launch time:
CD-ROM SourceDescription
NoneNo CD-ROM attached (default)
ImageMount an image (e.g., ISO) as a virtual CD-ROM drive
VolumeMount an existing volume as a CD-ROM drive
Xloud-Developed — The CD-ROM attachment feature in the instance create wizard is developed by Xloud and ships with XAVS / XPCI.

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CLI Block Device Mapping

Source credentials
source openrc.sh

openstack server create \
  --image <IMAGE_ID> \
  --boot-from-volume 50 \
  --flavor <FLAVOR> \
  --network <NETWORK> \
  my-instance
Block device mapping parameters:
ParameterValuesDescription
sourceimage, volume, snapshot, blankSource type for the block device
destvolume, localDestination — persistent volume or ephemeral local disk
idUUIDSource resource ID (for image, volume, or snapshot)
sizeInteger (GiB)Volume size
bootindex0 = boot, -1 = non-bootBoot order (0 for system disk)
shutdownremove, preserveDelete behavior on instance termination

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Volume Type Selection

When creating system or data disks, the available volume types depend on your platform’s storage backend configuration. Common tiers include:
TierTypical BackendUse Case
SSDCeph SSD pool or local NVMeDatabases, high-IOPS workloads
HDDCeph HDD pool or NFSArchival, log storage, bulk data
DefaultPlatform default tierGeneral-purpose workloads
Your administrator configures available volume types through XDeploy. The volume types shown in the instance wizard match those configured for the platform.

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Next Steps

Launch an Instance

Create an instance with the full 4-step wizard including disk configuration

Create a Volume

Pre-create volumes to attach as bootable or data disks

Volume Types

Understand available storage tiers and their characteristics

Instance Snapshots

Create snapshots of instances with their storage configuration