We use vSphere4.1 and we lack of disk space of vSphere.
Is it possible to export not recently used VM guests to Client PC temporarily safely and spare disk storage of ESXi ??
Export your VMs out as OVF templates
VMware vSphere 4 - ESX and vCenter Server
Thank you.
OVF,OVA export is usable for backup and it can be safely restored to original ESXi host ?
Yes, why not, treat them as your backup copy.
since you have mentioned you have some VM's which you are not using. so best is to export them out as OVF templates and free up the datastore space.
Later if you wish to import them back, they can be imported without much hassle.