[Kimchi-devel] [RFC] Create logical pool from existing VG

[Jose Ricardo Ziviani]

On 15-10-2015 13:12, Aline Manera wrote:
>
>
> On 15/10/2015 12:00, Jose Ricardo Ziviani wrote:
>>
>>
>> On 15-10-2015 11:56, Aline Manera wrote:
>>>
>>>
>>> On 15/10/2015 11:45, Jose Ricardo Ziviani wrote:
>>>> Hello,
>>>>
>>>> I'm about to write a new feature to Kimchi. It will allow users to
>>>> define any existing volume group as a storage pool, where guests will
>>>> be able to create logical volumes into it. NOTE: VGs already in use as
>>>> storage pool won't be listed.
>>>>
>>>> I read Pooja's "[RFC] Proposal to manage Physical Volumes on Ginger",
>>>> and now I think all LVM code should be implemented in WOK so both
>>>> plugins (Kimchi/Ginger) could take advantages from that.
>>>>
>>>> API:
>>>>
>>>> Collection: /plugins/kimchi/host/vgs
>>>> Method: GET
>>>> Returns: list of vgnames:
>>>> [vgname1, vgname2]
>>>>
>>>
>>> ACK
>>>
>>>> Resource: /plugins/kimchi/host/vg/vgname
>>>> Method: GET
>>>> Returns: dict
>>>> { vgname, size, free_size, [PV partition list, like: sda4, sdb3], [LV
>>>> name list, like: lv_root] }
>>>>
>>>
>>> ACK
>>>
>>>> Resource: /plugins/kimchi/storagepools/vgname
>>>> Method: POST
>>>> data: { vgname, storagepool_name, type=logical }
>>>
>>> I am little bit confused with this API. Usually the POST is done in a
>>> Collection so, something like:
>>>
>>> POST /plugins/kimchi/storagepools {name: pool_name, type: logical,
>>> vgname: vg_name}
>>>
>>> Is that what you are proposing?
>>
>> yes! updating:
>>
>> Collection: /plugins/kimchi/storagepools
>> Method: POST
>> data: {name: pool_name, type: logical, vgname: vg_name}
>>
>>>
>>>>
>>>> The frontend, I think we could have a table indicating all available
>>>> devices available for a logical storage pool, for example:
>>>>
>>>>
>>>> Define a New Storage Pool
>>>> 1. Storage Pool Name
>>>> +-----------------------------------------+
>>>> | mypool                                  |
>>>> +-----------------------------------------+
>>>> The name used to identify the storage pools, and it should not be
>>>> empty.
>>>>
>>>> 2. Storage Pool Type
>>>> +-----------+
>>>> | LOGICAL   |
>>>> +-----------+
>>>>
>>>> 3. Device path
>>>> +-------+-------+---------------+---------------+
>>>> |       |device | size        | free size    |
>>>> +-------+-------+---------------+---------------+
>>>> | ()     | sdb    | 50 GiB    | 50 GiB    |
>>>> +-------+-------+---------------+---------------+
>>>> | ()     | sdc    | 10 GiB    | 8 GiB        |
>>>> +-------+-------+---------------+---------------+
>>>> | ()    | vg_a    | 20 GiB    | 18 GiB    |
>>>> +-------+-------+---------------+---------------+
>>>>
>>>> +--------+
>>>> | Create |
>>>> +--------+
>>>
>>> May user select multiple VGs to create a logical pool? Or is it restrict
>>> to one by one, one VG, one logical pool?
>>> Depending on that, we need to redesign the UI
>>
>> Nope, my initial idea is to have 1 device to 1 storage pool. That's is
>> because users can group many partitions (PVs) into one VG.
>
> So I suggest to have separated options: one to create a logical pool
> from raw disks and other one to create a logical pool from an existing VG.


I see, so we will have:

2. Storage Pool Type
+--------------------------+
| (snip)
| LOGICAL                  |
| LOGICAL FROM EXISTING VG |
| (snip)                   |
+--------------------------+

and, suppose 'LOGICAL FROM EXISTING VG' is selected

+-------+---------------+---------------+---------------+
|	| device	| size		| free size	|
+-------+---------------+---------------+---------------+
|  ()   | vg_a          | 20 GiB	| 18 GiB	|
|  ()   | vg_b		| 10 GiB	| 5 GiB		|
+-------+---------------+---------------+---------------+

Any other pool type will keep unchanged.

Note: I intend to not list VGs without free space available. What do you 
think?
>
>>
>>>
>>>>
>>>> _______________________________________________
>>>> Kimchi-devel mailing list
>>>> Kimchi-devel at ovirt.org
>>>> http://lists.ovirt.org/mailman/listinfo/kimchi-devel
>>>>
>>>
>>
>

-- 
Jose Ricardo Ziviani
-----------------------------
Software Engineer
Linux Technology Center - IBM