[Link] vSphere VM quiescing essentials

  • 29 December 2020
  • 7 comments
  • 155 views

Userlevel 7
Badge +7
  • Veeam Legend, Veeam Vanguard
  • 1110 comments

Just read a excellent and very comprehensive article about VMware vSphere VM quiescing. This is the necessary process - within a VM - to get a consistent status of the guest OS (especially virtual disk) and applications. So VM gets quiesced before vSphere snapshot is created. Because VBR uses (like I think any other backup software vendor) vSphere snapshots for backup/replication, I thought this article would be interesting to share. It is definitely worth reading and I highly recommend to do so!

https://blog.zuthof.nl/2020/11/26/vsphere-vm-quiescing-essentials/

Here a short overview:

  • What is quiescing?
  • Consistency options
    • Non-quiesced
      • Crash consistent
    • Quiesced
      • File-system consistent
      • Application consistent 
        • Interfaces Veeam uses
          • Network (RPC)
          • vSphere VIX
        • Usage in
          • Windows
            • VSS
            • Script
          • Linux
            • Script
        • Quiescing impact on app recovery
          • Transaction Logs
  • Quiescing impact on performance
    • Snapshot based
      • Impact because of vSphere snapshot
      • Less impact with Storage snapshots (supported by Veeam)
    • IO Filter (VAIO)
      • For replication
        • in v10: Replication also uses vSphere Snapshots
        • in v11: CDP uses vSphere IO Filter as well
  • The role of VMware Tools
    • VMware Tools is its own product
    • Tools are back- and forward-compatible
    • Windows
      • Use current versions
      • Some driver are part of Windows Updates
    • Linux
      • Use open-vmware-tools

 

 


7 comments

Userlevel 7
Badge +6

Fantastic find :)

Userlevel 7
Badge +5

Very good explanation. 👍

Userlevel 7
Badge +6

Great post and a good future reference.

Regarding the compatibility of VMware tools quiescing on Linux. Is this in general limited to RHEL and SLES? And how does this affect backups of Linux VMs with Veeam?

Userlevel 7
Badge +7

Great post and a good future reference.

Regarding the compatibility of VMware tools quiescing on Linux. Is this in general limited to RHEL and SLES? And how does this affect backups of Linux VMs with Veeam?

@regnor I am afraid I do not understand. What “compatibility of VMware tools quiescing on Linux” do you mean?

open-vm-tools should be available for modern linux distributions in their own package management repository. When open-vm-tools is installed and running, quiescing and guest interaction should work.

Userlevel 7
Badge +6

I referred to the paragraph ‘Compatibility’ in the article. Although it's about vSphere replication the KB says that file system quiescing is only supported for RHEL and SLES.

Userlevel 7
Badge +7

I referred to the paragraph ‘Compatibility’ in the article. Although it's about vSphere replication the KB says that file system quiescing is only supported for RHEL and SLES.

Now I see your point, sorry for the delay :grin:  ! Yes, KB is related to vSphere Replication. In a quick research I did not find anything, that FS quiescing is not working on other distributions than RHEL or SLES. I will try to talk to customers about their experiences about this topic.

Userlevel 7
Badge +6

No problem at all :)

I haven’t had problems with Linux and file system quiescing before; I enable it per default and it works except for some special cases with appliances. It would just be good to know if it’s officially supported by VMware and/or if problems could occur.

Comment