disaster recovery strategies using ovirt's new storage connection management features...
DESCRIPTION
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.TRANSCRIPT
1Allon Mureinik - oVirt 3.3 Storage DR Features
Disaster Recovery Strategies Using oVirt's new Storage Connection Management
Features
Allon MureinikTeam Lead, Cloud Storage, Red [email protected] / @mureinik
February 2014
2Allon Mureinik - oVirt 3.3 Storage DR Features
Agenda
● Storage concepts in oVirt● Storage Domain vs. Storage Server Connection
● oVirt 3.3's new APIs and capabilities● GUI● REST
● Putting it all together● DR me, please!
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Terminology
“Language is the means of getting an idea from my brain into yours without surgery”
- Mark Amidon
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Terminology
● Disk – A virtual disk used by a VM (or template)● VDSM terminology: Image
● Storage Domain – A large storage area monitored and managed by oVirt.
● Main usage: Provisioning disks● Supported storage types:
● File Storage: NFS, GlusterFS, POSIX, local FS● Block Storage: iSCSI, FCP
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So what’s a Storage Server Connection?
● The “physical” properties where the “virtual” Storage Domain can be found
● For file storage – a [mount] path● For iSCSI – target details – iqn, port, username,
password, etc.● For FCP – not available
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Terminology – a visual representation
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What’s the problem? (pre 3.3)
● Users aren’t aware of Storage Server Connections
● Users aren’t aware of the distinction between them and Storage Domains
● GUI:● One screen to add● Part of Storage Domains management
● REST:● No such entity● Queried and added via Storage Domain operations
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What’s the problem – GUI (NFS)
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The Problem – GUI (iSCSI)
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What’s the problem - REST
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What’s new in oVirt 3.3?
● Storage Server Connections are an entity● They can be queried, added and updated independently
of the Storage Domains● ... And as such can be edited
● Supported for NFS, POSIX, local FS and iSCSI● Both via the GUI and via REST● Some advanced operations only available in REST
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GUI – File based Storage Domains
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REST – The main collection
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REST – A property of a Storage Domain
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Is there a DR in the house?
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Approach 1 – Network trickery only
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Approach 1 – Network trickery only (2)
● 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
● Extremely dangerous● Not flexible – requires similar (if not identical) hardware
configuration on both sites
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Approach 2 – Update the connection
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Approach 2 – Update the connection (2)
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Approach 2 – Update the connection (3)
● 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● Redundant for FCP, of course
● Advantage: Relatively simple
● Disadvantage: another step in an already elaborate process
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Approach 3 – Redundant Connections
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Approach 3 – Redundant Connections (2)
● 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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Looking forward
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Looking forward (no commitment)
● Support for GlusterFS
● Connection redundancy for file domains
● ISCSI multipathing (oVirt 3.4)
● Integrations● E.g. Symantec Cluster Server
● Patches are welcome!
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Where now?
● oVirt homepage:● http://www.ovirt.org
● Feature page:● http://www.ovirt.org/Features/Manage_Storage_Connections
● Lists:● [email protected]
● Feedback:● http://devconf.cz/f/117