Splitting a VM size and preformance question.

[offlinetn]

I found the answer for my first question at http://communities.vmware.com/message/770441#770441 that allows me to split a monolithic VM into 2 gig slices. Here are my next 2 questions.

1. Is there a MAX size of a monolithic VM that can be split?

2. Is there any performance problems with leaving the VM split and running it on the 2 gig slices or should I reassemble it back to the monolithic form?

Thanks!!!!

Chris Edwards

[SuperGrobi73]

Hallo Chris,

it is not a question of a maximum vmdk files allowed on a single vmfs volume, but you should keep in mind, that a growing file is always worse compared to the thick disk /monolithic disk in ESX.

VMFS is build for large files:

E.g. The I/O placed to an object in one VMDK that itself (the file, not the volume) is bigger than 2GB can cause a multi I/O Operation on the LUN, because 1,2, or 3 VMDH slizes have to be updated by the system. Another problem is fragmentation, when the LUN is becoming full the single 2gbsparces can be placed on different sectors of the LUN so condurrent write or read access can make the LUN respond slowly.

In my opinion, leaving on -flat.vmdk is much better for any operation compared ro sparced disks. If you want to export your VMDKs you can use VCB and split the one -flat.vmdk back to many 2gbsparces on your backup volume e.g. FAT32 or NTFS or what ever.

Carsten

[offlinetn]

Makes sense! Thanks for the answer and quick reply.

I still need to know if there is MAX size for a VM that can be split? Example.... Can I split a 200gig VM into 2gig slices? Can I split a 900gig VM into 2gig slices? The reason I want to know is to transport a very large VM accross the Internet.

Thanks!

Chris Edwards

[phenrichs · Accepted solution]

First, what version are you running? I ask because with newer versions you have additional options.

Your first question: The answer is no. There is no maximum size. The -d 2gbsparse is basically an export option, but they won't tell you that. If you are running 3.5 or 3i there is an OVF appliance that you can run that can convert the vm into smaller files and is a bit more efficient that the 2gbsparse option.

Question 2: I am afraid that this is not even an option. With either option I described above you are required to convert the vm back to one of the standard formats. It will not run from the 2gbsparse or the OVF format.

HOWEVER: If it is size that you are worried about you can create your VMs to dynamically allocate space using the thin format option. There are some pretty good docs regarding disk format on the site.

Regards,

Paul

[offlinetn]

We are running version 3.5. I need to break up an existing VM from a customer and transport it over a secure connection. Thanks for the help.