Okay, as for performance they're about the same.
With a 1gig NIC and a zfs mirror with 2x SATA2 drives I'm getting an average of about 105-110 MB/s write and about the same for read.
This is using dd on both read and write operations. I have three VM's operating on the LUN, two CentOS and one Windows 2008R2. With Windows update running on the WIndows server, software updates to the CentOS desktop and running dd on the CentOS server I'm achieving a lot of the same performance stats.
I will post more detail on that later.
I was expecting a little better performance with Comstar and Openindiana (OI) though, kind of disappointed really. The only issue's I've run into is I lost my iSCSI connection from the ESX host to the OI host a couple of times that caused corruption in the guest OSes. This kind of concerned me. I also noted RAM usage was higher for OI than FreeBSD.
To be fair, at first I left the defaults for ZFS in place for OI and had to tune a little bit such as setting the arc min and arc max. Here is the ZFS variables I changed on both installs:
On OI the settings similar and are set in /etc/system/
I'm going to leave the FreeBSD running overnight because with the OI install I got checksum errors on my zpool today after testing last night and this morning.--
"He's a politician. It's like being a hooker. You can't be one unless you can pretend to like people while you're f*cking them."