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Preparing for nondisruptive upgrades on systems with VMware ESX server hosts

Before performing a nondisruptive upgrade on storage systems exporting data over NFS to VMware ESX server hosts, you must verify that your client's NAS components are correctly configured, to ensure service availability for VMware guest operating systems during the upgrade.

About this task

These steps must be performed from the ESX server or guest operating systems, not from the storage system.

Steps

  1. Increase the NFS datastore's heartbeat time on the ESX server.

    The following parameters should be set to the recommended values:

    Parameter Value
    NFS.HeartbeatFrequency 12
    NFS.HeartbeatMaxFailures 10

    For more information about setting ESX server parameters, see the ESX documentation.

  2. Set the SCSI Disk timeout value on all guest operating systems to 190 seconds.

    You can obtain scripts to set the recommended SCSI disk settings in the guest operating systems for use with VMware ESX 3.5 and storage systems running Data ONTAP. When downloaded and run on the guest operating systems, the scripts create and modify the necessary files for each guest operating system type. Using the scripts ensures that the correct timeout settings are used in the guest operating systems to achieve maximum I/O resiliency when the guest operating systems are connected to storage systems.

    For more information about obtaining and running the scripts, see the knowledgebase article VMware ESX Guest OS I/O Timeout Settings for NetApp Storage Systems on the NetApp Support Site.

  3. Align the file systems that use virtual machine disk format (VMDK) on Windows with the storage systems' WAFL file system.

    This step is optional but recommended for best performance.

    Virtual machines store their data on virtual disks. As with physical disks, these disks are formatted with a file system. When formatting a virtual disk, the file systems with VMDK format, the datastore, and the storage array should be in proper alignment. Misalignment of the virtual machine’s file system can result in degraded performance.

    When aligning the partitions of virtual disks for use with storage systems, the starting partition offset value must be divisible by 4,096. The recommended starting offset value for Windows 2000, 2003, and XP operating systems is 32,768. Windows 2008 and Vista default at 1,048,576; that value does not require any adjustments.

    For more information about aligning virtual disks and WAFL file systems, see Virtual Machine Partition Alignment in the Technical Report NetApp and VMware Virtual Infrastructure 3, Storage Best Practices.