VMware Storage Migration

japplewhaite
japplewhaite used Ask the Experts™
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I did a storage migration this morning that took about four hours. I cloned this same VM to a different data store last Friday that took about an hour and thirty minutes. This morning I did a storage migration and it took four hours. Is this normal.
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The cloning process entirely depends on several factors which include the size of the VMDK file associated with the Virtual Machine, the type of datastore (whether Direct, SAN or NAS), the disk throughput available and the Network Bandwidth available if the migration is across the Network.
Top Expert 2010
Commented:
Are you inquiring is the completion time difference supposed to be so drastic? Yes, and let me explain why...
Cloning is simply a copy of a VM at a point in time. The time it takes to do the copy depends on the variables listed above by arunraju.
Storage vMotion on the other hand is *moving* the VMDK to another location while it's "live". The reason why this process takes longer is because of the underlying technology that goes on from the beginning to the end of the sVMotion process. A snapshot is created of the orig VMDK (virtual disk), while the orig is being transferred to the new location. If data is changed on the virtual disk being moved, it is written to the snapshot file. Once the orig virt disk is moved, the snapshot then 'commits' all data to the orig virt disk file. Depending on what data is being written to it, and again...the factors shared by arunraju, the process will take considerably longer.
A bit more 'high-level' info on sVMotion:
http://www.vmware.com/files/pdf/VMware-Storage-VMotion-DS-EN.pdf (pg. 2)

Regards,
~coolsport00

Regards,
~coolsport00
I would suggest that the points be split between arunraju and coolsport00.
Top Expert 2010

Commented:
Normally I would agree arunraju, but you didn't share much detail in your post. The factors you shared are certainly pertinent to the solution, but don't explain 'why' the discrepancy between the 2 transfer modes. Though your post has relevancy, it was incomplete, so I understand why the poster selected #33133839 as the  solution. That being said, what you posted was pertinent, so some points could have been awarded, but I don't believe an equal split. 300/200 or 400/100, or whatever the poster deems relevant.

~coolsport00
Well, if the poster deemed my solution to be incomplete, so be it.
I would like to clarify that your post seems to lay more emphasis on SVMotion and mine on cloning.
 
Top Expert 2010

Commented:
Not really; yours deals with both, because what you shared has bearing on both technologies; and mine deals with both. Cloning (as you're aware) is simply a copy...nothing more. The time it takes to clone depends solely on what you shared. sVMotion is much more than that, as I explained above. It involves what I posted *as well as* the same factors you shared. But, the poster wants to know why such a discrepancy in the time it takes to do each. The answer is because of what's being done with sVMotion. Yes, the other factors are involved, but sVMotion takes longer because of the processes involved during sVMotion migration. You can have equal bandwidth, NIC speeds, etc, etc...but the process will be longer because of how sVMotion works.

~coolsport00

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