By request in one meeting i write here my comments about the current way to select devices for create OSD's:
Maybe is good to share my experience trying to create OSD's using the dashboard.
The thing is that initially it was not possible for me to continue with the procedure because i dind't find the way to select a device as primary device and continue pressing the "add" button.(it was disabled all the time)
After receiving the explanations of the developers i understand that the "add" button only is going to be enabled when the right values has been entered in the selections fields placed over the list of available devices.
IMHO, this means that the current user interface to do this operation is not intuitive, and after understand the way it works, i think that is also a little bit uncomfortable. and in certain cases it makes imposible the selection of only one device. This is why:
When i'm going to select a primary/db/wal device for my OSD, I expect to see a list of possible devices to use. And that is exactly what is presented. But the next natural step for me, is if i can see the one that i want to use, then what i tend to do is just to select it and go to the next step ( in this case pressing the add button).
The problem is that this dialog box does not allow to select devices, it has been thought to make a valid selection trough the fields above the list of devices, and then go to the next step using as primary/db/wal devices all the devices listed in the dialog box.
IMHO, we should let the user select the device/s he wants to use in an explicit way, I mean, clicking directly over 1 or more rows,() using a button to select all the devices), and once the selection has been made, let the user go to the next step (press the "add" button).
The "selection" fields above the devices list should be used ( and indeed are very useful) to make easy to present the set of devices that are inside certain criteria (same host, type, size ...etc) but the selection should be done in an explicit way.
An example of doing the things in this way, is the basic creation of an OSD using only one device in a cluster with a small number of hosts.
With the possibility of device selection:
click 1: open add primary devices dialog toolbox
click 2: select the device i want to use.
click 3: press "add" button"
3 clicks and i almost do not need to think.
what we have in this moment:
click 1: open add primary devices dialog toolbox
i see the device i want to use, but i need to set the right mix of selection values to be able to have only this device in the screen.
click 2: I select type hdd. (in the screen i continue having more than one device , because all the host have )
click 3: I select the host where the device is installed. Now if i have several disks in this hosts, probably i will need to continue searching a way to differentiate the device that i am interested to use.
click 4-5-6: if i have luck and the disks installed in the hosts are different. probably using the size i will have only the device i wnat to have
click n: press "add" button"
For sure more than 3 clicks, and thinking about what i should to do in each of the selection clicks.
and ... if all the disks installed in one host are identical... it will not be possible to select only one device for my OSD.