Why are you moving away from FreeNAS?
Save money and get one 200GB DC3700. It will provide higher performance and the loss of an SLOG with a ZIL will no longer destory the pool on modern ZFS.
Yeah this isnt exactly true.. Intel actively markets their 730 drives to use in a RAID-0. Tests dont show a huge increase in OS related benchmarks but they certainly don't get worse.
It is just internal , correct?
Any LSI SAS2008 based HBA running in IT mode. An LSI SAS 9211-8i , an IBM M1015 flashed to IT mode.. numerous others. M1015's can had for about $100 off ebay but i do believe there have been some cheap knock-offs.
If you are going to pay full retail you might as...
something like http://www.ebay.com/itm/129281-001-HP-Compaq-64-bit-66Mhz-Wide-Ultra320-Dual-Channel-SCSI-PCI-Adapter-/231297277932?pt=US_Server_Disk_Controllers_RAID_Cards&hash=item35da645fec
should work
Will it even let you turn on writeback cache without a BBU?
If its for personal use id say you are probably fine.. if this is enterprise i would say get the BBU. UPS units do fail.
It should be using SMART data to pull the info from the drives and configure it, the problem can be when drives emulate 512b. I believe a lot of distro's are now forcing 4k because its far better to have 512b drives on 4k than vice-versa.
Run a "zdb | grep ashft" in the console, 9 is 512b...
Here is a comparison for Linux targets http://linux-iscsi.org/wiki/Features
FreeBSD is/has switched to a new native kernel implementation .. the latest FreeNAS has an "experimental mode" that enables it, and the next version it will be the default. .. lol getting even more off topic...
It wont help as a NAS OS drive, and i really think you need a lot of RAM in order for a L2 ARC to really benefit you much.
If you want to use sync writes you will a high quality one to use as an SLOG for the ZIL.
Otherwise spend your money elsewhere, like on more RAM.
That was in reference to NFS using sync writes moreso than the need to set sync=always if using NFS, It wont really make a difference as the writes will be synchronous anyway.
You seem to be suggesting that VM's know which writes need to be synced, which is false.
iSCSI absolutely needs...
False. ESXi has no clue as to the value, importance, or other attributes of the data that your VM is attempting to write. Just about every write will be sync write.
Not forcing sync on an ZFS pool containing a ESXi datastore is "fine" as long as you are fine with losing data and possibly...
In short, VMWare datastores over iSCSI and NFS need sync=always.
Your CIFS based local network probably doesnt need it.
Write performance will be terrible with sync=always unless you have a low latency SSD, ala Intel Enterprise ones.
If you are running OpenZFS, losing a SLOG device shouldn't be a disaster as long as you dont also lose power at the same time.
Speeds will slow to a crawl , however.
Ram requirements just depends on usage and performance requirements. 16GB should be fine for movie streams, but damn.. 42TB just for movies?
Freenas can have problems with less than 8GB these days i probably wouldnt go less than that.