that's the only way to go.   Storage vMpotion VMs off a datastore, then delete it in the ESX GUI.   Then put it offline in the EQL GUI, rescan all the ESX hosts, then you can delete the volume in the EQL GUI.   Repeat for the other volume, then create the smaller datastores.  If you are going to use VMDKs for SQL, make sure you have a separate VMDK for C:, Data and logs.  Then each VMDK needs its own virtual SCSI controller.   This will significantly improve performance.  By default,  ESX shares up to 15 VMDKs on a single virtual SCSI controller.    Alternatively, you can create dedicated volumes on the EQL array for SQL.  Then use the MS iSCSI initiatlor to connect to these volumes.  This would allow you to leverage the EQL HIT kit. 
We are using an EqualLogic PS6000 which is offered up to our VMWare vSphere 5.0 environment.  At the moment we have 9 volumes on the EqualLogic which in turn gives 9 Datastores within VMWare.  All our Virtual machines are spread across these volumes/datastores.  The problem that i have is that we have a critical SQL server that isn't playing nice with others if it has to share a volume/datastore with other VMs.  The SQL server is only around 300GB in size but all our volumes/datastores are 600GB plus, and i don't want to waste the remaining space and leave this one VM to take up a whole volume/datastore.  Can anyone suggest an easy way to either reduce the size of one of the 9 volumes in EqualLogic.  From my understanding this can't be done.  Or is my only option to move all VMs off one of the volumes/datastore so it is empty, then delete that volume on the EqualLogic and recreate 2 new volumes that are smaller in size?  Is this a safe way to go or can anyone see any problems with this?  Thanks
Question about recreating Volumes