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 VMware Cloud Director server group.

Each member of the server group mounts this volume at the same mountpoint: /opt/vmware/vcloud-director/data/transfer. Space on this volume is consumed in many ways, including:
  • 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 for which caching of the published content is enabled, 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.
Note: The volume of the transfer server storage must have capacity for future expansion.

Shared Storage Options

A traditional Linux-based NFS server or other solutions like Microsoft Windows Server, the VMware vSAN File Service NFS feature, and so on, can provide the shared storage. Starting with vSAN 7.0, you can use the vSAN File Service functionality to export NFS shares by using NFS 3.0 and NFS 4.1 protocols. For more information about vSAN File Service, see the Administering VMware vSAN guide in the VMware vSphere Product Documentation.

Requirements for Configuring the NFS Server

There are specific requirements for the NFS server configuration, so that VMware Cloud Director can write files to an NFS-based transfer server storage location and read files from it. Because of them, the vcloud user can perform the standard cloud operations and the root user can perform multi-cell log collection.
  • The export list for the NFS server must allow for each server member in your VMware Cloud Director server group to have read-write access to the shared location that is identified in the export list. This capability allows the vcloud user to write files to and read files from the shared location.
  • The NFS server must allow read-write access to the shared location by the root system account on each server in your VMware Cloud Director server group. This capability allows for collecting the logs from all cells at once in a single bundle using the vmware-vcd-support script with its multi-cell options. You can meet this requirement by using no_root_squash in the NFS export configuration for this shared location.

Linux NFS Server Example

If the Linux NFS server has a directory named vCDspace as the transfer space for the VMware Cloud Director server group with location /nfs/vCDspace, to export this directory, you must ensure that its ownership and permissions are root:root and 750. The method for allowing read-write access to the shared location for three cells named vCD-Cell1-IP, vCD-Cell2-IP, and vCD-Cell3-IP is the no_root_squash method. You must add the following lines to the /etc/exports file. 
/nfs/vCDspace vCD_Cell1_IP_Address(rw,sync,no_subtree_check,no_root_squash) 
/nfs/vCDspace vCD_Cell2_IP_Address(rw,sync,no_subtree_check,no_root_squash)
/nfs/vCDspace vCD_Cell3_IP_Address(rw,sync,no_subtree_check,no_root_squash)

There must be no space between each cell IP address and its immediate following left parenthesis in the export line. If the NFS server reboots while the cells are writing data to the shared location, the use of the sync option in the export configuration prevents data corruption in the shared location. The use of the no_subtree_check option in the export configuration improves reliability when a subdirectory of a file system is exported.

For each server in the VMware Cloud Director server group, you must have a corresponding entry in the NFS server's /etc/exports file so that they can all mount this NFS share. After making changes to the /etc/exports file on the NFS server, run exportfs -a to re-export all NFS shares.

Considerations When Planning to Upgrade Your VMware Cloud Director Installation to a Later Version

During an upgrade of a VMware Cloud Director server group, you run the installation file for the upgraded version to upgrade all the members of the VMware Cloud Director server group. For convenience, some organizations choose to download the installation file for the upgrade to the transfer server storage location and run it from there, because all the cells have access to that location. Because the root user must be used to run the upgrade installation file, if you want to use the transfer server storage location for running an upgrade, you must ensure that the root user can run the upgrade installation file when you are performing the upgrade. If you cannot run the upgrade as the root user, the file must be copied to another location where it can be run as the root user, for example, another directory outside the NFS mount.