To provide temporary storage for uploads, downloads, and catalog items that are published or subscribed externally, you must make an NFS or other shared storage volume accessible to all servers in a vCloud Director server group.
The vCloud Director appliance supports only NFS type of shared storage. The appliance deployment process involves mounting the NFS shared transfer server storage.
When NFS is used for the transfer server storage, you must configure each vCloud Director cell in the vCloud Director server group to mount and use the NFS-based transfer server storage. See http://kb.vmware.com/kb/2086127.
Each member of the server group must mount this volume at the same mountpoint, typically /opt/vmware/vcloud-director/data/transfer. Space on this volume is consumed in two ways:
During transfers, uploads and downloads occupy this storage. When the transfer finishes, the uploads and downloads are removed from the storage. Transfers that make no progress for 60 minutes are marked as expired and cleaned up by the system. Because transferred images can be large, it is a good practice to allocate at least several hundred gigabytes for this use.
Catalog items in catalogs that are published externally and enable caching of the published content occupy this storage. Items from catalogs that are published externally but do not enable caching do not occupy this storage. If you enable organizations in your cloud to create catalogs that are published externally, you can assume that hundreds or even thousands of catalog items require space on this volume. The size of each catalog item is about the size of a virtual machine in a compressed OVF form.
The volume of the transfer server storage must be easily expanded.