The mem node describing physical memory usage on the server is presented by complex type memStatType (plesk_server.xsd). The node is structured as follows:

• The total node is required. It returns the total amount of memory (in bytes) available on the server. Data type: size (common.xsd).
• The used node is required. It returns the amount of memory (in bytes) being used by different processes on the server. Data type: size (common.xsd).
• The free node is required. It returns the amount of free memory (in bytes) available on the server. Data type: size (common.xsd).
• The shared node is required. It returns the size (in bytes) of the shared memory segment. Data type: size (common.xsd).
• The buffer node is required. It returns the amount of memory (in bytes) used by system buffer. Data type: size (common.xsd).
• The cache node is required. It returns the amount of memory (in bytes) used by system cache. Data type: size (common.xsd).

The part of the response packet returning physical memory usage statistics may look as follows:

<mem>
   <total>2146910208</total>
   <used>2055024640</used>
   <free>91885568</free>
   <shared>0</shared>
   <buffer>0</buffer>
   <cached>0</cached>
</mem>