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Disk parameters |
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~~~~~~~~~~~~~~~ |
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The propose model for new disk parameters is a simple free-form one |
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based on dictionaries, indexed per disk level (template or logical disk) |
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and type (which depends on the level). At JSON level, since the object |
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key has to be a string, we can encode the keys via a separator |
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(e.g. slash), or by having two dict levels. |
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The proposed model for the new disk parameters is a simple free-form one |
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based on dictionaries, indexed per disk template and parameter name. |
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Only the disk template parameters are visible to the user, and those are |
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internally translated to logical disk level parameters. |
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This is a simplification, because each parameter is applied to a whole |
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nested structure and there is no way of fine-tuning each level's |
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parameters, but it is good enough for the current parameter set. This |
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model could need to be expanded, e.g., if support for three-nodes stacked |
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DRBD setups is added to Ganeti. |
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At JSON level, since the object key has to be a string, the keys can be |
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encoded via a separator (e.g. slash), or by having two dict levels. |
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+--------+-------------+-------------------------+---------------------+------+ |
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|Disk |Name |Description |Current status |Type | |
| 699 | 707 |
|template| | | | | |
| 700 | 708 |
+========+=============+=========================+=====================+======+ |
| 701 |
|dt/plain|stripes |How many stripes to use |Configured at |int |
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|plain |stripes |How many stripes to use |Configured at |int |
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| 702 | 710 |
| | |for newly created (plain)|./configure time, not| | |
| 703 | 711 |
| | |logical voumes |overridable at | | |
| 704 | 712 |
| | | |runtime | | |
| 705 | 713 |
+--------+-------------+-------------------------+---------------------+------+ |
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|dt/drdb |stripes |How many stripes to use |Same as for lvm |int |
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|drbd |stripes |How many stripes to use |Same as for plain |int |
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|
| 707 | 715 |
| | |for data volumes | | | |
| 708 | 716 |
+--------+-------------+-------------------------+---------------------+------+ |
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|dt/drbd |metavg |Default volume group for |Same as the main |string|
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|drbd |metavg |Default volume group for |Same as the main |string|
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|
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| | |the metadata LVs |volume group, | | |
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| | | |overridable via | | |
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| | | |'metavg' key | | |
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| | | | | | |
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+--------+-------------+-------------------------+---------------------+------+ |
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|dt/drbd |metastripes |How many stripes to use |Same as for lvm |int |
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|drbd |metastripes |How many stripes to use |Same as for lvm |int |
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|
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| | |for meta volumes |'stripes', suboptimal| | |
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| | | |as the meta LVs are | | |
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| | | |small | | |
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+--------+-------------+-------------------------+---------------------+------+ |
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|ld/drbd8|disk_barriers|What kind of barriers to |Either all enabled or|string|
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|drbd |disk_barriers|What kind of barriers to |Either all enabled or|string|
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| | |*disable* for disks; |all disabled, per | | |
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| | |either "n" or a string |./configure time | | |
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| | |containing a subset of |option | | |
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| | |"bfd" | | | |
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+--------+-------------+-------------------------+---------------------+------+ |
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|ld/drbd8|meta_barriers|Whether barriers are |Handled together with|bool |
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|drbd |meta_barriers|Whether barriers are |Handled together with|bool |
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|
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| | |enabled or not for the |disk_barriers | | |
| 728 | 735 |
| | |meta volume | | | |
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| | | | | | |
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+--------+-------------+-------------------------+---------------------+------+ |
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|ld/drbd8|resync_rate |The (static) resync rate |Hardcoded in |int |
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|drbd |resync_rate |The (static) resync rate |Hardcoded in |int |
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| | |for drbd, when using the |constants.py, not | | |
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| | |static syncer, in MiB/s |changeable via Ganeti| | |
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| | | | | | |
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| | | | | | |
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| | | | | | |
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+--------+-------------+-------------------------+---------------------+------+ |
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|ld/drbd8|disk_custom |Free-form string that |Not supported |string|
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|drbd |disk_custom |Free-form string that |Not supported |string|
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| | |will be appended to the | | | |
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| | |drbdsetup disk command | | | |
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| | |line, for custom options | | | |
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| | |not supported by Ganeti | | | |
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| | |itself | | | |
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+--------+-------------+-------------------------+---------------------+------+ |
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|ld/drbd8|net_custom |Free-form string for | | |
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|drbd |net_custom |Free-form string for |Not supported |string|
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| | |custom net setup options | | | |
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| | | | | | |
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| | | | | | |
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| | | | | | |
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| | | | | | |
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+--------+-------------+-------------------------+---------------------+------+ |
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Note that the DRBD8 parameters will change once we support DRBD 8.4, |
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which has changed syntax significantly; new syncer modes will be added |
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for that release. |
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Note that the DRBD parameters might change once Ganeti supports DRBD 8.4, in |
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which the :command:`drbdsetup` syntax has changed significantly. |
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Moreover, new parameters for the dynamic synchronization algorithm will |
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be added for DRBD versions >= 8.3.9. |
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All the above parameters are at cluster and node group level; as in |
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other parts of the code, the intention is that all nodes in a node group |
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should be equal. |
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should be equal. It will later be decided to which node group give |
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precedence in case of instances split over node groups. |
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.. admonition:: FIXME |
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Add details about when each parameter change takes effect (device |
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creation vs. activation) |
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Node parameters |
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~~~~~~~~~~~~~~~ |
Also available in: Unified diff