Datastore types

DataStores:
1.VMFS
2.NFS
3.Virtual SAN
4.Virtual Volumes


1.VMFS
supported version: VMFS5, VMFS3*
* you can still use VMFS3 but you cannot create new ones

VMFS5 characteristics:
-you can have up to 256 VMFS datastore per host with the maximum 64TB
-minimum  size for a VMFS datastore is 1.3Gb ( recommended min 2GB)
-greater than 2TB storage devices
*VMFS3 has a 2TB limit
-greater than 2TB disk sizes for RDM
-support of small files of 1KB
-standard 1MB file system block size with support of 2TB disk files
- ability to open any file on a VMFS5 datastore in shared mode ( with 32 hosts)

2. NFS
supported version : NFSv3, NFSv4.1

NFSv3
-supports hardware acceleration ( to be used with thik provisioning)
-storage traffic is tranmitted unencrypted
-cannot access the NFS volumes with nontroot credetials; each host needs root access to the volume
-does not support multipath
-locking protocol is created by vmware ( does not support NLM) implemented by creating lock files on the NFS server ( .lck-file_id)
NFSv4.1
-does not support hardware acceleration
-supports Kerberos authentication prtocol to secure comunication with the NFS server
-supports nonroot users to access files when used with Kerberos
-supports multipath for server that support session trunking
*client ID trunking is not supported
-supports inbuilt file locking
-uses shares and rezervation are a locking mechanism

vSphere feature support:     NFSv3 NFSv4
vMotion&StoragevMotion     y          y
HA                                          y          y
FT                                           y          y
DRS                                        y          y
Host-Profiles                          y          y
Storage-DRS                          y          n
Storage I/O control                 y          n
Site Recovey manager            y          n
Virtual volumes                      y          n

3. Virtual SAN
-creates an aggregated datastore by clustering host attached HDDs and SSDs
- you enable it at cluster level and  it creates a data store using the storage component of all hosts in the cluster
- is mounted using Object Store File System
-can be configured as:
a: hybrid : HDD and SSD for datastore, all-flash for read cache/write buffer
b: all-flash storage:SSD ?  all-flash for  write cache

4. Virtual Volumes
- native representation of VMDK files
-works with existing SAN/NAS volumes
-supports snapshots/replications,etc
-storage containers can expand an entire array

sources:
http://pubs.vmware.com/vsphere-60/topic/com.vmware.ICbase/PDF/vsphere-esxi-vcenter-server-601-storage-guide.pdf