Delphix storage migration allows you to remove storage devices from your Delphix Engine, provided there is sufficient unused space, thus allowing you to repurpose the removed storage device to a different server. You can also use this feature to migrate your Delphix Engine to different storage by adding the new storage devices and then removing the old storage devices.
Note: This feature is only compatible for Delphix Engine Releases 5.0.4 and later.
Please be aware of the following technical bulletins:
Understanding Delphix Storage Migration
Delphix storage migration is a multi-step process:
- Identify a storage device for removal. The device you choose will depend on your use case.
To remove extra storage that is unused, you can select any device for removal. For best performance, select the device with the least allocated space; typically, this is the device that you added most recently. The allocated space is defined by the
usedSizeproperty of the storage device:
areece-test1.dcenter 'Disk10:2'> ls Properties type: ConfiguredStorageDevice name: Disk10:2 bootDevice: false configured: true expandableSize: 0B model: Virtual disk reference: STORAGE_DEVICE-6000c293733774b7bb0e4aea83513b36 serial: 6000c293733774b7bb0e4aea83513b36 size: 8GB usedSize: 7.56MB vendor: VMware
- To migrate the Delphix Engine to new storage, add storage devices backed by the new storage to the Delphix Engine. Then remove all the devices on the old storage.
- Use the Delphix command line interface (CLI) to initiate the removal of your selected device.
- Data will be migrated from the selected storage device to the other configured storage devices. This process will take longer the more data there is to move; for very large disks, it could potentially take hours. You can cancel this step if necessary.
- The status of the device changes from configured to unconfigured and an alert is generated to inform you that you can safely detach the storage device from the Delphix Engine. After this point, it is not possible to undo the removal, although it is possible to add the storage device back to the Delphix Engine.
- Use the hypervisor to detach the storage device from the Delphix Engine. After this point, the Delphix Engine is no longer using the storage device, and you can safely re-use or destroy it.
Limitations of Delphix Storage Migration
After a removal, the Delphix Engine uses memory to track the removed data. In the worst-case scenario, this could be as much as 1GB of memory per 1TB of used storage. Note that this is used storage; the overhead of removing a 1TB device with only 500MB of data on it will be much lower than the overhead of removing a 10GB device with 5GB of data on it.
Delphix storage migration is currently available exclusively via the CLI. There are 3 entry points:
storage/remove –The status of the current or most recent removal, including the total memory used by all removals up to this point
storage/device “$device”/removeVerify –Returns the predicted effect of removing the selected device, or an error if the device cannot be removed
storage/device “$device”/remove –Begins the evacuation and removal of the selected device
Device Removal for Storage Migration
Identify which device you want to remove.
If you are using a VMware RDM disk, note the UUID of the device by looking at its name in the vSphere GUI. For more information, see this Getting the UUID of a RDM Disk from vmware, via the vSphere GUI.
If you are using a VMware virtual disk, note the UUID of the device via the vSphere API. See the section of this VMware KB article on how to get the UUID of your virtual disk.
In EC2, note the attachment point – for example,
In KVM, note the UUID.
Login to the Delphix CLI as a sysadmin user and navigate to
Select your device:
areece-test1.dcenter storage device> ls Objects NAME CONFIGURED SIZE EXPANDABLESIZE Disk10:2 true 8GB 0B Disk10:0 true 24GB 0B Disk10:1 true 8GB 0B Disk10:3 true 8GB 0B areece-test1.dcenter.dcenter storage device> select Disk10:2
(VMware only) Confirm that your disk selection is correct by validating that the serial matches your UUID:
areece-test1.dcenter storage device 'Disk10:2'> ls Properties type: ConfiguredStorageDevice name: Disk10:2 bootDevice: false configured: true expandableSize: 0B model: Virtual disk reference: STORAGE_DEVICE-6000c2909ccd9d3e4b5d62d733c5112f serial: 6000c2909ccd9d3e4b5d62d733c5112f size: 8GB usedSize: 8.02MB vendor: VMware
removeVerifyto confirm that removal will succeed. Validate the amount of memory/storage used by the removal:
areece-test1 storage device 'Disk10:2'> removeVerify areece-test1 storage device 'Disk10:2' removeVerify *> commit type: StorageDeviceRemovalVerifyResult newFreeBytes: 15.85GB newMappingMemory: 3.14KB oldFreeBytes: 23.79GB oldMappingMemory: 0B
removeto start the device evacuation:
areece-test1 storage device 'Disk10:2'> remove areece-test1 storage device 'Disk10:2' remove *> commit Dispatched job JOB-1 STORAGE_DEVICE_REMOVAL job started for "Disk10:2". 0.63GB out of 0.68GB remaining. 0.59GB out of 0.68GB remaining. ...
Wait for device evacuation to complete. Alternatively, you can cancel the evacuation.
Do NOT detach the device from the Delphix Engine in your hypervisor until after the data evacuation has completed.
The screenshot below illustrates a progress bar for completion.
Once the device evacuation has completed, the job will finish and a fault will be generated. Detach the disk from your hypervisor and the fault will clear on its own. An example of the fault created is seen below.
When using VMDKs, deleting the wrong VMDK could cause data loss. Therefore, it is highly advisable to detach the device, then verify that the Delphix Engine continues to operate correctly, and lastly delete the VMDK.
Getting the UUID of a RDM Disk from VMware, via the vSphere GUI
In the ESX graphical user interface (GUI), select your VM.
- Click Edit settings.
- If not already displayed, select the Hardware tab.
- Select the device you want to remove.
Click Manage Paths.
The UUID of the device appears in the title bar, as seen below.
Getting the UUID of a VMDK from VMware, via ssh to the ESX server
- ssh onto the ESX server as the root user
- Navigate to the directory containing the .vmdk files for the Delphix VM
Use the 'vmkfstools -J getuuid <.vmdk filename>' command to obtain the UUID, for example
/vmfs/volumes/25894daa-f7b2b044/delphix01-2356 # vmkfstools -J getuuid delphix01-2356_1.vmdk UUID is 60 00 C2 91 01 bc 8e 72-31 a4 cd b0 b3 f6 e5 74