Solved the problem by explicitly specifying the data type

$resize = 'VDI.resize';
$xcpapi->$resize($vdi, ''.(int)$hdd2.'');

Doesn't work without brackets

''.(int)$hdd2.''

Thank you for introducing the possibilities XO, but everyone is free to choose their own path. Sorry, but the question is not about the capabilities of XO, I would like to hear who can help me ..

Of course I'm familiar with Xen Orchestra, but it doesn't suit me.

1. Integration with CRM.
2. Integration with the company's website.
3. I am learning and it is very pleasant to do something myself, time does not matter.

Hello everyone.
I am developing management of VMs via the web.
Faced the problem of resizing the disk.
To change I use the VDI.resize function
I cannot understand this function in what format does it accept data B, KB, MB, GB?
If I transfer to Byte, writes an error

API failure. (SR_BACKEND_FAILURE_79 VDI Invalid size [opterr = VDI size must be between 1 MB and 2088960 MB])

If I transfer to KB .... an error

API failure. (SR_BACKEND_FAILURE_79 VDI Invalid size [opterr = shrinking not allowed])

Maybe someone knows how to do it right?