Live Storage Migration in oVirt - over and under the hood

1. Live Storage Migration in oVirt
Over and Under the Hood
Allon Mureinik
Team Lead, Cloud Storage, Red Hat
May 2013
Allon Mureinik - Live Storage Migration Over and Under Hood
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2. A bird’s eye view of oVirt
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3. “Language is the means of
getting an idea from my
brain into yours without
surgery.”
(Mark Amidon)
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4. oVirt Architecture
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5. Live Storage Migration
Over the Hood
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6. Live Storage Migration in a Nutshell
Definition
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The capability to move one or more VM Disks from one
storage to another without interrupting the guest
operations
Motivation
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Facilitate storage hardware upgrades
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Assist smarter disk provisioning
●
Allow storage re-purposing
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7. A Picture is Worth 1024 Words
Host A
Host A
VM
Virtual Disk
Storage A
Storage B
VM
Virtual Disk
Storage A
Storage B
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8. Live Storage Migration
Under the Hood
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9. Flow Overview 1/4 – Initial State
Volume 1
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10. Flow Overview 2/4 – Live Snapshot
Volume 1
Volume 1
Volume 2
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11. Flow Overview 3/4 – Replica & Copy
Volume 1
Volume 1
Volume 2
Volume 1
Volume 2
Volume 1'
Volume 2'
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12. Flow Overview 4/4 - Completion
Volume 1
Volume 1
Volume 2
Volume 1
Volume 2
Volume 1'
Volume 2'
Volume 1'
Volume 2'
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13. Error Handling
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If any error occurs before the copy/replica is
completed:
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Replication is stopped
The volumes on the destination domain are deleted
If any error occurs after the copy/replica is completed:
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The VM is essentially OK
●
Junk on the source domain should be cleaned up
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14. Looking Forward
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15. Road Map
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Allow Live Storage Migration of multiple VM disks
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Integrate live merge and don’t keep the snapshot
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Supported in QEMU, requires integration
Snapshot only the migrated disk
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Done in oVirt 3.2
Mainly a UI/management issue
Combine with Live VM Migration
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16. How to get involved?
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Main project site:
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Useful wikis
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http://www.ovirt.org
http://www.ovirt.org/Features/Design/StorageLiveMigration
Mailing Lists:
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users@ovirt.org
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arch@ovirt.org
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engine-devel@ovirt.org
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vdsm-devel@lists.fedorahosted.org
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17. Q&A
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