Confirming a virtual machine's snapshot delta disk layout
Article ID: 304387
Updated On:
Products
VMware vCenter Server
VMware vSphere ESXi
Issue/Introduction
This article provides instructions on reviewing virtual machine snapshot configurations and detailing snapshot delta disk trees.
Environment
VMware VirtualCenter 2.0.x
VMware vSphere ESXi 5.5
VMware ESXi 4.1.x Embedded
VMware ESXi 4.1.x Installable
VMware ESX 4.0.x
VMware vCenter Server 5.0.x
VMware ESXi 4.0.x Embedded
VMware ESXi 3.5.x Embedded
VMware ESXi 3.5.x Installable
VMware vCenter Server 4.1.x
VMware vCenter Server 4.0.x
VMware VirtualCenter 2.5.x
VMware vSphere ESXi 5.1
VMware vSphere ESXi 5.0
VMware ESX Server 3.5.x
VMware ESXi 4.0.x Installable
VMware ESX Server 3.0.x
VMware ESX 4.1.x
VMware vSphere ESXi 5.5
VMware ESXi 4.1.x Embedded
VMware ESXi 4.1.x Installable
VMware ESX 4.0.x
VMware vCenter Server 5.0.x
VMware ESXi 4.0.x Embedded
VMware ESXi 3.5.x Embedded
VMware ESXi 3.5.x Installable
VMware vCenter Server 4.1.x
VMware vCenter Server 4.0.x
VMware VirtualCenter 2.5.x
VMware vSphere ESXi 5.1
VMware vSphere ESXi 5.0
VMware ESX Server 3.5.x
VMware ESXi 4.0.x Installable
VMware ESX Server 3.0.x
VMware ESX 4.1.x
Resolution
The virtual machine's snapshot database (.vmsd file) contains information about the snapshot layout and disk delta sequence for a virtual machine. This database is interpreted for the VMware vSphere or Infrastructure Client, and lists existing virtual machine snapshots as a whole. It does not go into detail about the individual delta disk files which make up part of the virtual machine's snapshot state. For such information, you must log into the ESXi/ESX host terminal.
Note: If the snapshot manager does not contain any snapshot entries, yet the virtual machine continues to run snapshot delta disks, see Committing snapshots when there are no snapshot entries in the Snapshot Manager (1002310).
If you have multiple virtual machine disks located across other datastores, the delta disks for all virtual disks are by default stored in the same location. For example:
Ultimately, examplevm-000001.vmdk uses examplevm.vmdk as its parent, which is the base disk for the virtual machine.
Alternatively, if there were additional snapshotted disks to consider, the tree layout may appear similar to:
Note: Absolute paths suggest that the extent or disk is located on another datastore. Relative paths are used for files in the same directory.
Note: If the snapshot manager does not contain any snapshot entries, yet the virtual machine continues to run snapshot delta disks, see Committing snapshots when there are no snapshot entries in the Snapshot Manager (1002310).
Confirming a virtual machine's snapshot delta disk layout using the ESXi/ESX host terminal
Note: For instructions on logging into an ESXi/ESX host terminal, see the Additional Information section of this article.If you have multiple virtual machine disks located across other datastores, the delta disks for all virtual disks are by default stored in the same location. For example:
/vmfs/volumes/datastore1/examplevm/examplevm.vmdkWhen a virtual machine snapshot is created, all attached non-independent disks are snapshotted simultaneously. As such, there will be one delta disk per virtual machine disk, per snapshot. The colors above indicate what delta disks are related to either specific base disk. Thus, the three snapshots would have created a total of six delta files in datastore1/examplevm:
/vmfs/volumes/datastore2/examplevm/examplevm_secondary_disk.vmdk
/vmfs/volumes/datastore1/examplevm/examplevm-000001.vmdkFurther details are required to understand which snapshot delta file relates to any one disk. The ordering of these snapshots should also be understood. Run the following command tTo lay out the snapshot delta disk tree, run the command:
/vmfs/volumes/datastore1/examplevm/examplevm-000002.vmdk
/vmfs/volumes/datastore1/examplevm/examplevm-000003.vmdk
/vmfs/volumes/datastore1/examplevm/examplevm-000004.vmdk
/vmfs/volumes/datastore1/examplevm/examplevm-000005.vmdk
/vmfs/volumes/datastore1/examplevm/examplevm-000006.vmdk
...
/vmfs/volumes/datastore1/examplevm/examplevm.vmdk
/vmfs/volumes/datastore1/examplevm/examplevm.vmx
grep -A2 parentFile examplevm-???????.vmdk | grep -v "#"You see output similar to:
examplevm-000001.vmdk:parentFileNameHint="examplevm.vmdk"This indicates that the descriptor file examplevm-000003.vmdk has an extent (stored delta information) of examplevm-000003-delta.vmdk. It uses examplevm-000002.vmdk as its parent disk, which uses examplevm-000001.vmdk as its parent.
examplevm-000001.vmdk-RW 41943040 VMFSSPARSE "examplevm-000001-delta.vmdk"
--
examplevm-000002.vmdk:parentFileNameHint="examplevm-000001.vmdk"
examplevm-000002.vmdk-RW 41943040 VMFSSPARSE "examplevm-000002-delta.vmdk"
--
examplevm-000003.vmdk:parentFileNameHint="examplevm-000002.vmdk"
examplevm-000003.vmdk-RW 41943040 VMFSSPARSE "examplevm-000003-delta.vmdk"
Ultimately, examplevm-000001.vmdk uses examplevm.vmdk as its parent, which is the base disk for the virtual machine.
Alternatively, if there were additional snapshotted disks to consider, the tree layout may appear similar to:
examplevm-000001.vmdk:parentFileNameHint="examplevm.vmdk"In this case, the odd-numbered snapshot delta disks are related to the first virtual hard disk, and the even-numbered files are related to the secondary virtual hard disk.
examplevm-000001.vmdk-RW 41943040 VMFSSPARSE "examplevm-000001-delta.vmdk"
--
examplevm-000002.vmdk:parentFileNameHint="/vmfs/volumes/4b96afb0-b2474ede-fc0b-001aa004abc2/examplevm/examplevm_1.vmdk"
examplevm-000002.vmdk-RW 23123440 VMFSSPARSE "examplevm-000002-delta.vmdk"
--
examplevm-000003.vmdk:parentFileNameHint="examplevm-000001.vmdk"
examplevm-000003.vmdk-RW 41943040 VMFSSPARSE "examplevm-000003-delta.vmdk"
--
examplevm-000004.vmdk:parentFileNameHint="examplevm-000002.vmdk"
examplevm-000004.vmdk-RW 23123440 VMFSSPARSE "examplevm-000004-delta.vmdk"
--
examplevm-000005.vmdk:parentFileNameHint="examplevm-000003.vmdk"
examplevm-000005.vmdk-RW 41943040 VMFSSPARSE "examplevm-000005-delta.vmdk"
--
examplevm-000006.vmdk:parentFileNameHint="examplevm-000004.vmdk"
examplevm-000006.vmdk-RW 23123440 VMFSSPARSE "examplevm-000006-delta.vmdk"
Note: Absolute paths suggest that the extent or disk is located on another datastore. Relative paths are used for files in the same directory.
Additional Information
Logging into an ESXi/ESX host terminal
- For VMware ESXi 4.1 and 5.x, see Using Tech Support Mode in ESXi 4.1 and ESXi 5.x (1017910).
- For VMware ESX, log in directly at the console by pressing Alt + F1 and using the
rootuser's credentials, or log in using SSH. For more information, see Connecting to an ESX host using a SSH client (1019852). - For VMware ESXi 4.0 and 3.5, see Tech Support Mode for Emergency Support (1003677).
Virtual machine snapshots and delta disks
- For more information on virtual machine snapshot and delta disk files, see Understanding virtual machine snapshots in VMware ESXi and ESX (1015180).
- For more information on snapshot and delta disk consolidation or removal, see Consolidating snapshots in vSphere 5.x (2003638) or Consolidating snapshots in ESX/ESXi 3.x and 4.x (1007849).
- For more information on snapshot removal or consolidation when the snapshot manager is non-functional, see Committing snapshots when there are no snapshot entries in the snapshot manager (1002310).
Committing snapshots when there are no snapshot entries in the Snapshot Manager
Tech Support Mode for Emergency Support
Consolidating snapshots in ESX/ESXi 3.x and 4.x
Understanding VM snapshots in ESXi / ESX
Using Tech Support Mode in ESXi 4.1, ESXi 5.x, and ESXi 6.x
Connecting to an ESX host using an SSH client
How to consolidate snapshots in vSphere 5.x/6.x
确认虚拟机的快照增量磁盘布局
仮想マシンのスナップショット差分ディスク レイアウトの確認
Confirmação do layout de disco delta de instantâneo de uma máquina virtual
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