A short overview of oVirt 3.3's Storage Connection Management feature, and several examples how this feature can be used in Disaster Recovery strategies.

1. Disaster Recovery Strategies Using oVirt's
new Storage Connection Management
Features
Allon Mureinik
Team Lead, Cloud Storage, Red Hat
amureini@redhat.com / @mureinik
February 2014
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2. Agenda
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Storage concepts in oVirt
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Storage Domain vs. Storage Server Connection
oVirt 3.3's new APIs and capabilities
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GUI
REST
Putting it all together
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DR me, please!
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3. Terminology
“Language is the
means of getting an
idea from my brain into
yours without surgery”
- Mark Amidon
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4. Terminology
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Disk – A virtual disk used by a VM (or template)
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VDSM terminology: Image
Storage Domain – A large storage area monitored and
managed by oVirt.
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Main usage: Provisioning disks
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Supported storage types:
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File Storage: NFS, GlusterFS, POSIX, local FS
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Block Storage: iSCSI, FCP
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5. So what’s a Storage Server Connection?
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The “physical” properties where the “virtual” Storage
Domain can be found
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For file storage – a [mount] path
For iSCSI – target details – iqn, port, username,
password, etc.
For FCP – not available
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6. Terminology – a visual representation
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7. What’s the problem? (pre 3.3)
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Users aren’t aware of Storage Server Connections
Users aren’t aware of the distinction between them and
Storage Domains
GUI:
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One screen to add
Part of Storage Domains management
REST:
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No such entity
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Queried and added via Storage Domain operations
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8. What’s the problem – GUI (NFS)
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9. The Problem – GUI (iSCSI)
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10. What’s the problem - REST
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11. What’s new in oVirt 3.3?
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Storage Server Connections are an entity
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They can be queried, added and updated independently
of the Storage Domains
... And as such can be edited
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Supported for NFS, POSIX, local FS and iSCSI
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Both via the GUI and via REST
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Some advanced operations only available in REST
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12. GUI – File based Storage Domains
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13. REST – The main collection
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14. REST – A property of a Storage Domain
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15. Is there a DR in the house?
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16. Approach 1 – Network trickery only
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17. Approach 1 – Network trickery only (2)
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When the DR site comes up, oVrit Engine sends the
same connection details to the new hosts
Luckily, the DR site has its own DNS server, and the
old connection details just point to the replicated
storage
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Extremely dangerous
Not flexible – requires similar (if not identical) hardware
configuration on both sites
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18. Approach 2 – Update the connection
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19. Approach 2 – Update the connection (2)
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20. Approach 2 – Update the connection (3)
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When switching over to the DR site, use the REST API
to edit the connection details for all storage domains
Applicable for NFS, POSIX and iSCSI
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Redundant for FCP, of course
Advantage: Relatively simple
Disadvantage: another step in an already elaborate
process
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21. Approach 3 – Redundant Connections
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22. Approach 3 – Redundant Connections (2)
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User REST API to add connection to all the storage
servers, including the DR site, when the site is
established
Make sure, via network configuration, that each host
can only access one storage server, so there aren’t
any “collisions”
Advantage: Preemptive, less steps when switching
over to a DR site
Disadvantage: Additional “useless” information in the
production site
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23. Looking forward
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24. Looking forward (no commitment)
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Support for GlusterFS
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Connection redundancy for file domains
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ISCSI multipathing (oVirt 3.4)
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Integrations
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E.g. Symantec Cluster Server
Patches are welcome!
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25. Where now?
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oVirt homepage:
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Feature page:
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http://www.ovirt.org/Features/Manage_Storage_Connections
Lists:
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http://www.ovirt.org
users@ovirt.org
Feedback:
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http://devconf.cz/f/117
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