Virtual disk migration takes too long

[cjells55]

Hi, I am in the process of migrating virtual disks to another datastore and the process is exceedingly slow. After 1 hour, the progress bar states 20% . At this rate, it will take several hours to complete the task.  I am migrating three virtual disks (all thin provisioned) from one NFS datastore to another. The sizes are:

100 GB

300 GB

15 GB

That would be the fully provisioned size. The actual usage is much less, as the disks have about 75 % free space, except fot the 15 GB disk which has about 3 GB free.

I am using the migrate function in VCenter to do this, by right clicking the VM, then choosing "migrate", then change datastore, then advanced, then selecting the new datastore for only the three virtual disks that I wish to migrate, leaving everything else set at "Current Location".

I am doing this with the VM powered off, and with the configuration file, and hard disk 1, and swap partition remaining in the same datastore.

Any ideas on why it would take so long or how to speed it up?

Thanks

[Pieter Du Preez]

Hi

Any ideas on why it would take so long or how to speed it up?

What is your network speed for the NFS storage? The higher the speed the faster the Migration

Also, the time is calculated on the entire size which is 475GB, even though only 200GB might be actual data.

Seeing it is thin provisioned, what you will see is the copy running slow while it is copying data for example the first 50% but then there after the progrees bar will move toward 100% very fast because the are no actual data to copy, just the provisioned space.

So it will not be a case of 1hour = 20% which totals 5hours to do the full migration

I will estimate it will take between 2.5 to 3 hours (Calculated guess :smileywink:)

Hope all that makes sense :smileywink:

Please award points if you find this helpful/correct :smileycool:

[cjells55]

Thanks for your reply. The network speed is GB for the storage network.  Yes, I am hoping that the copy speed for the space that contains no data is faster, and it does appear that this is happening as the % in the status field is moving faster at least at this time and is now at 68% after two hours.

I should mention that I chose the option 'same format as the source" when prompted for the storage provisioning.  The disks that I am moving are all thin provisioned, though.

also: this is ESX 4.0.0.0 build 261974

Thanks

[Pieter Du Preez]

So my prediction of 2.5 to 3 hours might be right :smileyhappy:

I should mention that I chose the option 'same format as the source" when prompted for the storage provisioning.  The disks that I am moving are all thin provisioned, though.

This should be fine as long as these disk were not inflated by a full format.

Please remember to award points for correct/helpful posts by clicking the Tabs :smileywink:

[cjells55]

Yes, it looks that way. It does slow down when it hits the data part of the disk ansd then speeds up,  and it looks like the time to move the data files will be in that range, so your answer is correct.

Thanks for your help!

[farkasharry]

There is a faster way to move files: Use vmkfstool on the CLI. Shutdown VM's and move them with it. It was about 4times faster for me!