> > > > This is not entirely correct either. You're not forced to use VMFS. >
It is entirely true. You absolutely cannot use ESX with a guest on a block device without formatting the LUN with VMFS. You are *FORCED* to use VMFS. You can format the LUN with VMFS, then put VM files inside the VMFS; in this > case you get the Guest OS filesystem inside a VMDK file on the VMFS > filesystem inside a LUN/ZVOL on your ZFS filesystem. You can also set up Raw > Device Mapping (RDM) directly to a LUN, in which case you get the Guest OS > filesystem inside the LUN/ZVOL on your ZFS filesystem. There has to be VMFS > available somewhere to store metadata, though. > > You cannot boot a VM off an RDM. You *HAVE* to use VMFS with block devices for your guest operating systems. Regardless, we aren't talking about RDM's, we're talking about storing virtual machines. It was and may still be common to use RDM for VMs that need very high IO > performance. It also used to be the only supported way to get thin > provisioning for an individual VM disk. However, VMware regularly makes a > lot of noise about how VMFS does not hurt performance enough to outweigh its > benefits anymore, and thin provisioning has been a native/supported feature > on VMFS datastores since 4.0. > > I still think there are reasons why iSCSI would be better than NFS and vice > versa. > > I'd love for you to name one. Short of a piss-poor NFS server implementation, I've never once seen iSCSI beat out NFS in a VMware environment. I have however seen countless examples of their "clustered filesystem" causing permanent SCSI locks on a LUN that result in an entire datastore going offline. --Tim
_______________________________________________ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
