Host partition layout

XenServer 7.0 introduced a new host disk partition layout. By moving log files to a larger, separate partition, XenServer can store more detailed logs for a longer time. This feature improves the ability to diagnose issues. Simultaneously, the new partition layout relieves demands on Dom0’s root disk and avoids potential space issues due to log file disk space consumption. The default layout contains the following partitions:

  • 18 GB Citrix Hypervisor server control domain (dom0) partition

  • 18 GB backup partition

  • 4 GB logs partition

  • 1 GB swap partition

  • 0.5 GB UEFI boot partition

In XenServer 6.5 and earlier releases, the 4 GB control domain (dom0) partition was used for all dom0 functions, including swap and logging. Customers who do not use remote syslog or who used with third-party monitoring tools and supplemental packs found the size of the partition to be limited. Citrix Hypervisor eliminates this issue and provides a dedicated 18 GB partition to dom0. In addition, a larger partition dedicated to dom0 reduces demand on the dom0 root disk which can offer significant performance improvements.

The introduction of the 4 GB dedicated log partition eliminates scenarios where excessive logging filled up the dom0 partition and affected the behavior of the host. This partition also enables customers to retain a detailed list of logs for a longer time, improving the ability to diagnose issues.

The partition layout also contains a dedicated 500 MB partition required for UEFI boot.

Note:

If you install Citrix Hypervisor with the new partition layout described above, ensure that you have a disk that is at least 46 GB in size.

To install Citrix Hypervisor on smaller devices, you can do a clean installation of Citrix Hypervisor using the legacy DOS partition layout. A small device is one that has more than 12 GB but less than 46 GB disk space. For more information, see Installing on Small Devices.

Important:

We recommend that you allocate a minimum of 46 GB disk space and install Citrix Hypervisor using the new GPT partition layout.

Legacy partition layout

Note:

The legacy DOS partition layout is deprecated and will be removed in a future release.

  • XenServer 5.6 Service Pack 2 and earlier used DOS partition tables to separate the root file system and backups from the local storage.

  • XenServer 6.0 introduced GUID partition tables to separate root file system, backup and local storage.

  • Installing Citrix Hypervisor 8.1 on machines with a required initial partition that must be preserved continues to use the DOS partitioning scheme.

The following table lists the installation and upgrade scenarios and the partition layout that is applied after these operations:

Operation Number of partitions before upgrade Number of partitions after installation/upgrade Partition table type
Clean installation with at least 46 GB of primary disk space N/A 6 New GPT
Clean installation with disable-gpt with a minimum of 12 GB of primary disk space N/A 3 (or 4 if there is a utility partition) DOS
Clean installation on a machine with a utility partition N/A 3 (or 4 if there is a utility partition) DOS

Host partition layout