handsy
Enthusiast
Enthusiast

Snapshotting of VM causing NTP time drift - should I use Tools to sync instead?

I have Veeam taking nightly backups of some large VMs. Each night at the time of snapshotting/consolidation, NTP spikes and drifts back in time approximately 30 minutes!

I'm thinking of using VMWare Tools to sync time on these VMs instead.

Anyone have any comments on that please?

Thanks

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5 Replies
pragg12
Hot Shot
Hot Shot

Hi,

How many and how large VMs we are talking about here ?

What troubleshooting steps /analysis have you performed till now ?

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handsy
Enthusiast
Enthusiast

6x VMs - varying no. of CPUs from 6 to 14, varying memory from 64GB to 128GB, i.e. large VMs.

I've tinkered with NTP till the cows come home, I've increased CPU shares to HIGH for all of these VMs.

I've not tried to reserve CPU yet, or disabled NTP and tried sync'ing through Tools.

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pragg12
Hot Shot
Hot Shot

Ok.

Need some more insight into the affected VMs as my initial guess is that your issue maybe due to snapshot since only 6 VMs are facing the issue.

1. Since when you are facing the NTP issue ?

2. Around the time as per ques 1, any changes in VMs/backup/storage infrastructure made ?

3. Total size of each VM w.r.t disk?

4. Any active or manual snapshot on VMs before backup snapshot process starts ?

5. What is the stun time for each VM when snapshot process occurs (when VM is not accessible over network) ?

6. What's the underlying storage type for these VMs? HDD or SSD ?

Consider marking this response as "Correct" or "Helpful" if you think my response helped you in any way.
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Rubeck
Virtuoso
Virtuoso

You can disable the "back drifting" of time by editing the VMs .vmx file..

VMware Knowledge Base 

Not ideal.... but it should work.

/Rubeck  

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handsy
Enthusiast
Enthusiast

Think I'm gonna try this option....only problem is it's a power off of VM.

Maintenance window here I come!

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