JustyC
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Moving large VM to new datastores

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Read some of the other discussions on this topic .... I have a slight twist... can someone offer guidelines\options on the best way to relocate a very large VM

from a NetApp array to a EMC VNX array.  The VM has 4 disks  -  2 of which are 1+ TB each and currently runs on a ESX 4.0 host.  We want to move the

datastores and guest to a new ESXi 5 host.  Can be 2 steps if necessary.  Taking any downtime will be difficult and must be kept to a minimum.  I've used vMotion

and Converter.  A vMotion test generated a block size complaint.  Converter is very slow and often times out.  If the guest can be powered off I can use the datastore

browser to move the .VMDKs, then unregister\re-register the .vmx.  Slow maybe, but should be better than Converter.  Unfortunately the 4 disks are all separate datastores

and therefore do not reside with the dtatastore containing the .vmx.  Can I still do this by modifying the .vmx to point to the new disk locations ?

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a_p_
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The reason I'm trying to find out whether Storage vMotion is possible, is mainly to avoid downtime. With an ESXi 5 host which has access to all datastores you can Storage vMtotion the powered on VM, regardless of VMFS versions and block sizes. However, keep in mind that migrating between different block sizes is slower that migrating with between datastores with the same block size.

André

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schepp
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Hi,

what licenses do you have for the ESXi 5 hosts?

When you install ESXi 5.5, you have Storage vMotion available with Standard licenses and above.

So you could transfer the VM without any downtime, if you can connect the datastores and the CPUs are vMotion compatible:

1. Connect ESXi 5.5 to the old storage

2. vMotion the VM to the new host

3. Storage vMotion the VM to the new datastores

a_p_
Leadership
Leadership

>>> A vMotion test generated a block size complaint.

Running Storage vMotion from a 4.x host requires a VMFS3 target datastore with at least a 4 MB (maybe 8MB) block size. Can you confirm the target datastore has been created with the appropriate block size.

André

JustyC
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We have ESXi 5 Enterprise Plus licensing.  The host we want to move to is ESXi 5.0.  Unfortunately,

it does not see the NetApp array where the guest currently runs.

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JustyC
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Yes, the block size is a problem.  The guest is currently VMFS3 block 8.  I was testing using storage vMotion to another VMFS datastore with block size 4, which was

one of the few datstores with enough free space.  It wasn't happy.  Ideally, I'd like to get it to a VMFS5 datastore.

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a_p_
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Please provide some details about your environment, to find out what might be possible.

  • How does the environment currently look like, i.e. do you manage the 4.x and 5.x hosts using the same vCenter instance?
  • Which ESXi host versions do you currently use?
  • Is upgrading to ESXi 5.1 or newer an option? This would allow to live migrate the VM without the requirement for the same shared storage.
  • Is it possible to attach all required datastores (NetApp as well as VNX) to an ESXi 5 host for the purpose of the migration? Even adding a temporary ESXi host (running in evaluation mode) to the vCenter Server would do.

André

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JustyC
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Andre... 50-50 on the environment.  Half the hosts are ESX 4.0 U2 - the other half ESXi 5.0 U2.  All are managed

by one vCenter.  We are planning to upgrade vCenter to 5.5, rebuild the 4.0 hosts to 5.5 and then upgrade the 5.0 hosts to 5.5

in a few months.  It should be possible to build a test 5.0 host with an eval license that sees the NetApp and VNX array, then use

vMotion to move the datastores.  Would there be any issues moving vmfs3 block 8 datastores to vmfs5 block 1 ?  You seem

to be leaning towards vMotion and not using the data browser way.  vMotion would probably be faster and safer.

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a_p_
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The reason I'm trying to find out whether Storage vMotion is possible, is mainly to avoid downtime. With an ESXi 5 host which has access to all datastores you can Storage vMtotion the powered on VM, regardless of VMFS versions and block sizes. However, keep in mind that migrating between different block sizes is slower that migrating with between datastores with the same block size.

André

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