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Device Mapper FOSDEM Sunday 27th February 2005 Alasdair Kergon agk@redhat.com

What is Device Mapper?

What Device Mapper is not

Userspace Architecture

Device Mapper Kernel Architecture

Mapped Devices

Device Referencing

Original Logical Volume

Add Copy On Write Logical Volume

Insert Snapshot Layers

Read a Block from Origin

Read a Block from Snapshot

Write a Block to Origin(1) – Notify Snapshot

Write a Block to Origin (2) – Write

Write a Block to Origin – Summary

Write Any Block to Snapshot

Read a Changed Snapshot Block

Single Snapshot Summary

Two Snapshots

Mirror – pvmove

Mirror – pvmove – Before

Mirror – pvmove – After

Mirror – pvmove - During

Multipath Architecture

dm-ioctl (2)

dm-ioctl – Versioning

dm-ioctl – DM_VERSION

dm-ioctl – DM_LIST_VERSIONS

dm-ioctl - DM_DEV_CREATE

dm-ioctl – Referencing devices

dm-ioctl - DM_DEV_REMOVE

dm-ioctl - DM_REMOVE_ALL

dm-ioctl - DM_DEV_RENAME

dm-ioctl - DM_LIST_DEVICES

dm-ioctl - DM_TABLE_LOAD

dm-ioctl - DM_TABLE_CLEAR

dm-ioctl - DM_SUSPEND

dm-ioctl - info

dm-ioctl - DM_TABLE_STATUS

dm-ioctl - DM_DEV_WAIT

dm-ioctl - DM_TABLE_DEPS

dm-ioctl - DM_TARGET_MSG

libdevmapper

Logical Volume Management

Advantages of LVM

LVM2 Design Goals: Learn from LVM1

Some LVM commands

LVM2 Tool Enhancements (1)

LVM2 Tool Enhancements (2)

LVM2 Tool Enhancements (3)

LVM2 Tool Enhancements (4)

Text Metadata Format (1)

Text Metadata Format (2)