disk / partition / volume structure

[fed.linuxgossip]

Hi,

In applogic grid, the amount of available disk space is about less than half of the actual space ( consider some part of the boot volume and impex ) , because Everything is mirrored which means it takes twice the space.

Is the above point correct ?

Is there any docs that explaining the disk / partition / volume structure and the way data is handled in them.



Thanks

[Chris]

http://doc.3tera.com/AppLogic2/ReleaseNotes-2-1-0.html

5. The total available disk space does not take volume mirroring into account
The total available disk space reported by the grid info command is a raw estimate and does not take volume mirroring into account. The true available disk space is the reported available amount divided by the number of mirrors (2 mirrors by default). For example, if there is 1000GB of available disk space and the grid was configured for mirroring of 2, the available disk space is 500GB. Also, in order to successfully mirror volumes, there must be enough disk space on at least X servers where X is the number of mirrors (AppLogic will not fail to create a volume if any one of its mirrors cannot be created, it will display a warning that the volume could not be mirrored).

[PeterNic]

Chris, thanks for providing the info.

Fed, is there any other info you need. In its default configuration, AppLogic essentially joins all disks within each server (so if you have multiple disks, they are concatenated into one big storage structure); individual volumes are then mirrored across 2 servers (so a 10G volume takes 20G of raw space). That's pretty much it.

Regards,
-- Peter