
Note:
You can use the BRAND_CONSOLE; Repair Storage Repository function to retry the PBD creation and plugging portions of the
NFS VHD
The NFS VHD type stores disks as VHD files on a remote NFS filesystem.
NFS is a ubiquitous form of storage infrastructure that is available in many environments. XenServer allows existing NFS servers that support NFS V3 over TCP/IP to be used immediately as a storage repository for virtual disks (VDIs). VDIs are stored in the Microsoft VHD format only. Moreover, as NFS SRs can be shared, VDIs stored in a shared SR allow VMs to be started on any XenServer hosts in a resource pool and be migrated between them using XenMotion with no noticeable downtime.
Creating an NFS SR requires the hostname or IP address of the NFS server. The
As mentioned at the beginning of this chapter, VDIs stored on NFS are sparse. The image file is allocated as the VM writes data into the disk. This has the considerable benefit that VM image files take up only as much space on the NFS storage as is required. If a 100GB VDI is allocated for a new VM and an OS is installed, the VDI file will only reflect the size of the OS data that has been written to the disk rather than the entire 100GB.
VHD files may also be chained, allowing two VDIs to share common data. In cases where a
Note:
The maximum supported length of VHD chains is 30.
As
XenServer's NFS and VHD implementations assume that they have full control over the SR directory on the NFS server. Administrators should not modify the contents of the SR directory, as this can risk corrupting the contents of VDIs.
XenServer has been tuned for
In situations where XenServer is used with
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