datastore space

Moving VMs or reducing the storage (virtual machine disk) size, will increase the space on the datastore.

either use Migrate, Storage vMotion, Copy/Paste or VMware vCenter Srandlone Converter.

to a new datastore, also check for snapshots.

see my EE Article, Step by Step Tutorial Instructions with Screenshots

HOW TO: VMware Snapshots :- Be Patient

HOW TO: Backup (Export) and Restore (Import) virtual machines to VMware vSphere Hypervisor 5.1 for FREE

HOW TO:  P2V, V2V for FREE - VMware vCenter Converter Standalone 5.5

HOW TO:  Synchronize changes when completing a P2V or V2V with VMware vCenter Converter Standalone 5.1

HOW TO: "Live Migrate" VMware Virtual Machines between ESX/ESXi hosts and/or datastores for FREE without licenses for vMotion or Storage vMotion

HOW TO: Clone or Copy a virtual machine in VMware vSphere Hypervisor ESX/ESXi 4.x or ESXi 5.0

HOW TO: Improve the transfer rate of a Physical to Virtual (P2V), Virtual to Virtual Conversion (V2V) using VMware vCenter Converter Standalone 5.0

You can increase datastore capacity if this is LUN assigned from SAN..
http://pubs.vmware.com/vsphere-4-esx-vcenter/index.jsp?topic=/com.vmware.vsphere.server_configclassic.doc_41/esx_server_config/managing_storage/t_increase_vmfs_datastores.html

Or you can add another storage as new data store and then move VMs across..

thanks

I have deleted some space on the VM and this did not help.
How can I reclaim these space.

Even though you may be see any snapshots list in the GUI for your VM's you still may have an orphan snapshot connected to a VM. I would suggest browseing your datastore folder and check for VM with VMDK like:  vmname_0001.vmdk.

Check for any crash dump logs as well.

Remove any unsed ISO / install files.

You could try to do an inplace storage migration to change your VM's from thick to thin provisioned.

I was told that storage venders have their own tools to reclaim the space, like netapp has vsc, dell has hit etc. I am going to talk to them.
in th eman time I am going to do storage motion.