Loading

×Sorry to interrupt
Uncaught ReferenceError: addCTracking is not defined
throws at https://kb.vmware.com/resource/KM_TealiumTrackingJS?v=0.5:100:1

Refresh

Cookie Preference Center

General Information on cookies

When you visit our website, we use cookies to ensure that we give you the best experience. This information does not usually directly identify you, but it can give you a more personalized web experience. Because we respect your right to privacy, you can choose not to allow some types of cookies by clicking on the different category headings to find out more and change your settings. However, blocking some types of cookies may impact your experience on the site and the services we are able to offer. Further information can be found in our

Cookie Policy.

Strictly Necessary

Strictly Necessary

Always Active

Strictly Necessary

Strictly necessary cookies are always enabled since they are essential for our website to function. They enable core functionality such as security, network management, and website accessibility. You can set your browser to block or alert you about these cookies, but this may affect how the website functions. For more information please visit www.aboutcookies.org or www.allaboutcookies.org.

Cookie Details‎

Performance

Performance

Performance

Performance cookies are used to analyze the user experience to improve our website by collecting and reporting information on how you use it. They allow us to know which pages are the most and least popular, see how visitors move around the site, optimize our website and make it easier to navigate.

Cookie Details‎

Please confirm your settings by refreshing the page.

Functional

Functional

Functional

Functional cookies help us keep track of your past browsing choices so we can improve usability and customize your experience. These cookies enable the website to remember your preferred settings, language preferences, location and other customizable elements such as font or text size. If you do not allow these cookies, then some or all of these services may not function properly.

Cookie Details‎

Advertising

Advertising

Advertising

Advertising cookies are used to send you relevant advertising and promotional information. They may be set through our site by third parties to build a profile of your interests and show you relevant advertisements on other sites. These cookies do not directly store personal information, but their function is based on uniquely identifying your browser and internet device.

Cookie Details‎

Advertising Cookies

Consent Leg.Interest

Select All Vendors

Select All Vendors

Select All Hosts

Select All

Clear Filters

Information storage and access

Apply

Confirm My Choices Reject All Allow All

My Subscriptions

Loading

Knowledge Base

vSAN svMotion caveats/considerations (74997)

Last Updated: 11/5/2023Categories: TroubleshootingTotal Views: 3886Language:
English

Subscribe to get an email
newsletter with new updates

Please provide article feedback:

Symptoms

When running a svMotion for a virtual machine from vSAN to an external storage or vice versa you see the error "Insufficient disk space on datastore." when it appears the destination datastore has sufficient space.

svMotion compatibility precheck fails with the error "the vmdk is larger than the maximum size supported by the datastore."

Cause

This is due to svMotion calculating the destination space required for the migration based on the storage policy in use for the VM/vmdk. This also impacts svMotion checking a vmdk is not larger than the maximum allowed 62TB size for a vSAN datastore.

For example, if migrating a 1TB VM with an FTT=1 (Mirroring) it's consuming 2TB on vSAN so when migrating the VM to external storage it's expecting 2TB of free space even though it will only use 1TB on external storage.

The same applies to migrating a 1 TB VM from external storage to vSAN. If using a storage policy of FTT=1 then 2TB of free space is required on vSAN to migrate the VM.

If a vmdk is provisioned for 50TB with a RAID1 policy then svMotion will calculate it as 100TB so this will result in the Compatibility precheck failing with the error "the vmdk is larger than the maximum size supported by the datastore"

If using RAID5 this will be 50TB x 1.33 which equals 66.5TB which is larger than the 62TB maximum allowed vmdk size. See vSAN Configuration Limits for more details.

For more information regarding vSAN FTT see the below docs:
vSAN Policies
Planning Capacity in vSAN
Demystifying Capacity Reporting in vSAN
RAID-1, RAID-5 or RAID-6 - What to choose?
Understanding the Impact of Number of Failures to Tolerate
Adaptive RAID-5 Erasure Coding with the Express Storage Architecture in vSAN 8

Impact / Risks

svMotion tasks may fail to complete.

Resolution

To work around this issue ensure there are current and valid backups of the VM/vmdk to be svMotioned and then do one of the following:

Ensure the datastore the VM is being migrated to has the required space to accommodate the provisioned space plus the FTT in use of the storage policy

If you have a current and valid backup of the VM/vmdk you can restore from backup to the destination datastore

If migrating a large vmdk of 32TB or more with FTT=1 policy to another vSAN datastore change the policy to FTT=2/3 if it will allow for the size to be under the max vmdk size of 62TB otherwise you'll need to change it to FTT=0

If going from vSAN to external storage and the datastore has enough space to accommodate the VM/vmdk provisioned space but not provisioned plus FTT follow the steps below:

Ensure there is plenty of free space on the vSAN datastore and if there is change the vSAN Storage Policy to FTT=0.

Wait for the resync to complete if going from FTT=2/3 to FTT=0

svMotion the virtual machine.

Note: Keep in mind following this action plan has its risks as the VM/vmdk will no longer have redundancy which is why it's important to confirm you have backups prior to performing the svMotion.

A proactive approach is to take these considerations into perspective when planning out VM deployments on vSAN.

For more information see About the vSAN Default Storage Policy

Detectable by VMware SkylineTM

Actions

Copy

link to clipboard
copied!

Print

Language:
English

Attachments

Additional Resources

KB
•
[VMC on AWS] VMware HCX の導入後にパブリック IP アドレスが自動的に割り当てられる (75035)

Result 1 of 1

Ask The Community

Get answers quickly from VMware experts in the community

Post Subject

CONTINUE IN COMMUNITIES

Related Products:

VMware vSAN

Related Versions:

Take Our Survey

Support Assistant