Page History

...

VM Host Profile Parameters

General Parameters

Name

...

• Descriptive name of the VM host profile

...

Storage Parameters

Datastore Path

...

• Location where master copies of images are stored which are used by running VMs
• Example: /vmfs/volumes/nfs-datastore1

  Info
  For ESXi, the path configured in the profile may simply be the short datastore name as it appears in the vSphere Client: nfs-datastore1

• Storage location should be large enough to store all of the images which may be loaded on the VM host (from 100's of GB to several TB)
• VCL creates a directory for each image in the datastore
• Images are stored in the vmfs thin vmdk format
• Datastore Path may either reside on local or network storage
• Multiple VM hosts can share the same datastore if network storage is used
  • A single datastore may be used by all VM hosts if performance is adequate
  • Multiple VMs on different hosts may access the same Datastore Path image at the same time
  • It is recommended that datastores are shared among hosts so that fewer copies of each image have to be stored
  • The underlying storage hardware and network connectivity from the hosts to the storage must be adequate
  • Storage where the datastore is located should be optimized for read performance
• VCL configures VMs to access images stored in the Datastore Path in read-only mode
  • Changes made to the VM's hard drive are written to delta files located in the VM Path directory dedicated for the VM

...

• Path where master copies of images are stored which are used to transfer images to VM host datastores or to other repositories:
  • If a reservation is assigned to a host but the image does not exist in that host's datastore, it is copied from the repository to the datastore path when the VM is loaded
  • If the VCL environment contains multiple management nodes and the image does not exist in the repository or the host's datastore, the image will be retrieved from another management node's repository by copying it via SCP
• The Repository Path parameter does not need to be configured if the VCL environment contains a single management node and all VM hosts share the same Datastore Path
• Example: /vmfs/volumes/nfs-repository1
• VMs do not run directly off of the images stored in the repository
• Setting the Repository Path parameter determines whether or not an additional copy of an image is created when an image is captured
  • If repository path is not configured then only a single copy of the image will exist in the datastore after an image is captured
  • If repository path is configured then two copies of the image will exist after an image is captured - one in the datastore and one in the repository
• Repository Path location can refer to and be mounted on either the management node or VM host
  • It is highly recommended that the repository be mounted on the VM host
    • When mounted on the VM host, vmdk operations can be done directly on the VM host in a single step
• Images in the repository are stored in the 2 GB sparse vmdk format
  • The size of the vmdk files will approximately be equal to the amount of actual data saved in the image regardless of the size of the VM's hard drive
  • Storing images in the 2 GB sparse format is necessary to allow images to be transferred via SCP without having to transfer data equal to the entire size of the VM's hard driveExample: A Linux image contains is allocated a 30 GB hard drive but only 800 MB is actually used. A copy of the image is stored in both the datastore (thin vmdk) and repository (2 GB sparse vmdk).  Each of these locations is mounted via NFS on the VM host and management node.
  • The size of the 2 GB sparse vmdk files will be approximately equal to the actual amount of data used according to both the ls and du commands from the management node:

    Panel

    Wiki Markup \[root@vcl-mn vmwarelinux-RHEL54Small2251-v0\]# ls \-lh \-rwxr-xr-x 1 root root 880M Apr 22  2011 vmwarelinux-RHEL54Small2251-v0-s001.vmdk ... \-rwxr-xr-x 1 root root 1.5K Apr 22  2011 vmwarelinux-RHEL54Small2251-v0.vmdk total 798M \[root@vcl-mn vmwarelinux-RHEL54Small2251-v0\]# du \-ch \*.vmdk 406M    vmwarelinux-RHEL54Small2251-v0-s001.vmdk ... 16K     vmwarelinux-RHEL54Small2251-v0-s016.vmdk 8.0K    vmwarelinux-RHEL54Small2251-v0.vmdk 798M    total

  The size of the thin vmdk file will be equal to the size of the VM's hard drive according to the ls command from the management node:

  Panel
  Wiki Markup \[root@vcl-mn vmwarelinux-RHEL54Small2251-v0\]# ls \-lh total 953M -rw-\-----\- 1 root root *30G* Aug  1  2011 vmwarelinux-RHEL54Small2251-v0-flat.vmdk -rw-\-----\- 1 root root 540 Aug  2  2011 vmwarelinux-RHEL54Small2251-v0.vmdk

  • The size of the thin vmdk file will be approximately equal to the actual amount of data used according to the du command from the management node:

    Panel
    Wiki Markup \[root@vcl-mn vmwarelinux-RHEL54Small2251-v0\]# du \-ch \*.vmdk 953M    vmwarelinux-RHEL54Small2251-v0-flat.vmdk 8.0K    vmwarelinux-RHEL54Small2251-v0.vmdk 953M    total

  • Copy the thin vmdk via SCP - the amount of data copied is equal to the size of the VM's hard drive (30 GB):

    Panel
    Wiki Markup \[root@vcl-mn nfs-datastore1\]# scp \-r vmwarelinux-RHEL54Small2251-v0 matilda:/install/thin vmwarelinux-RHEL54Small2251-v0-flat.vmdk                                                      7% 2261MB  25.3MB/s   18:45 ETA

  Copy the 2 GB sparse vmdk via SCP - the amount of data copied is approximately equal to the actual amount of data used: Panel Wiki Markup\[root@vcl-mn vmware_images\]# scp \-r vmwarelinux-RHEL54Small2251-v0 matilda:/install/2gbsparse vmwarelinux-RHEL54Small2251-v0-s001.vmdk                                                    100%  880MB  25.9MB/s   00:34 ... vmwarelinux-RHEL54Small2251-v0-s016.vmdk                                                    100%   64KB  64.0KB/s   00:00 vmwarelinux-RHEL54Small2251-v0.vmdk                                                         100% 1444     1.4KB/s   00:00

VM Disk

• Defines whether the storage where the VM host's Datastore Path resides is dedicated to a single host or shared among multiple hosts:
  • localdisk
    • The VM host's Datastore Path is located on local disks or dedicated network storage
    • The VM host is the only host which accesses the Datastore Path
    • Repository Path must be configured
  • networkdisk
    • The VM host's Datastore Path is located on network storage which is shared by other VM hosts
    • Repository Path is optional

...