CrossPoolMigrationv2: Difference between revisions
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m (moved CrossPoolMigrationv1 to CrossPoolMigrationv1 tmp: CrossPoolMigration v1 and v2 were the wrong way round.) |
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{{TODO|Has this been implemented? If so, it should be moved to Designs in the XAPI Devel Index}} |
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<!-- Original date: Mon Jul 18 15:07:12 2011 (1311001632000000) --> |
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__NOTOC__ |
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This page describes a possible design for [[CrossPoolMigration|Cross-pool migration]] (which also works for within-pool migration with and without shared storage). |
This page describes a possible design for [[CrossPoolMigration|Cross-pool migration]] (which also works for within-pool migration with and without shared storage). |
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This is an alternative design to [[ |
This is an alternative design to [[CrossPoolMigrationv1]] and [[CrossPoolMigrationv3]]. |
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This design has the following features: |
This design has the following features: |
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The [https://github.com/djs55/iscsi-target-manager iscsi-target-manager] is a simple python program which wraps the "tgtadm" commands used to configure an iSCSI target. |
The [https://github.com/djs55/iscsi-target-manager iscsi-target-manager] is a simple python program which wraps the "tgtadm" commands used to configure an iSCSI target. |
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[[Category: |
[[Category:XAPI Devel]] |
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[[Category:Developers]] |
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Latest revision as of 13:02, 11 July 2013
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To Do:
Has this been implemented? If so, it should be moved to Designs in the XAPI Devel Index |
This page describes a possible design for Cross-pool migration (which also works for within-pool migration with and without shared storage).
This is an alternative design to CrossPoolMigrationv1 and CrossPoolMigrationv3.
This design has the following features:
- tapdisk log-dirty is used to build an efficient continuous disk copy program
- this is storage-format agnostic: it doesn't require .vhd
- the SM on one host can generate URIs which can be used by other SMs to access disks over iSCSI on the storage network
- handling of iSCSI endpoints (both initiators and targets) is abstracted by an iSCSI service
- this is expected to simplify the current code and prevent (eg) a bug in one SM plugin from interfering with another SM plugin
- a single codepath is used in xapi, making testing easier
- this replaces the existing migration API
- a simple RESTful API makes the whole thing quite easy to test, prod etc.
- the xapi pieces and the SM pieces can be developed and tested independently and integrated at the end
Component diagram
Migration sequence
Proposed milestones and task list
The following milestones are proposed:
| Milestone number |
| 1 |
| 2 |
| 3 |
| 4 |
The following tasks are proposed:
| Task | Status |
| Forward-port blktap1 log dirty mode to tapdisk2 | |
| Implement an iSCSI service in dom0 | Completed |
| Modify VDI.deactivate to finish any pending copies | |
| Implement xapi HTTP operations | |
| Create a continuous copy program (use sparse_dd?) | |
| Implement SMAPI VDI.copy | |
| Implement SMAPI VDI.get_url | |
| Implement XenAPI VM.migrate, VM.receive | |
| Implement xapi HTTP heartbeat |
Links
The iscsi-target-manager is a simple python program which wraps the "tgtadm" commands used to configure an iSCSI target.
