Performance- FreeNAS + Vista
Since running Vista on my iozone test machine had helped goose the performance of the Windows Home Server based system in Fast NAS Part 3, I decided to see if it would help with a NAS that wasn't using Microsoft SMB, TCP/IP or file copy code.
I also noticed the performance improvement suggestions at the bottom of the FreeNAS CIFS/SMB settings page (Figure 6), so decided to try enabling the Large read/write (shown) and Tuning (System:Advanced page) options, too.
Figure 6: FreeNAS CIFS performance improvement options
To keep the graphs uncluttered, Figure 7 shows a comparison of only RAID 0 write performance with these variations:
- RAID 0 - original configuration. No CIFS Tweaks. Win XP2 on iozone machine
- RAID 0 Vista SP1 - Same as #1, but with Vista SP1 on iozone machine
- RAID 0 Vista SP1 HD - Same as #2, but with FreeNAS installed on IDE hard drive
- RAID 0 Vista SP1 HD Tun Lg - Same as #3, but with FreeNAS Large read/write and Tuning options enabled
Note that I expanded the tests to include a 4 GB file size, so that both the iozone 512 MB and FreeNAS 2 GB memories were exceeded during the test. I also dropped the D-Link from the chart, since I didn't have any RAID 0 mode data handy.
Figure 7: Atom Write performance - FreeNAS w/ Vista, CIFS tweaks
The tests with FreeNAS running from an IDE hard drive were just to convince myself that there was no performance penalty from running the OS from a flash drive (or vice versa). The bottom line from these tests is that Vista SP1 alone didn't provide write throughput improvement, but enabling the Large read/write and Tuning options did.
Figure 8 tells a different story for reads, however. This time, it is Vista that provides a read speed boost, with no difference from enabling the Large read/write and Tuning options.
Figure 8: Atom Read performance - FreeNAS w/ Vista, CIFS tweaks
So it looks like the combination of the Intel Atom mobo, a gigabit PCI NIC, FreeNAS with Large read/write and Tuning tweaks enabled and Vista SP1 running on a client, yield a NAS with slightly-better write and much better read performance than you can get from an off-the-shelf, comparably-priced dual-drive NAS. The extra performance comes at a $20 - $50 premium and 2X power consumption compared to the D-Link DNS-321/323, however. And, at least for my build, the Atom-based result isn't anywhere near as small or attractive!
But the Atom-based NAS also didn't come anywhere near bumping up against the 67 MB/s single-spindle SATA drive limit that I found in my tests of NASes using beefier CPUs. And I also didn't see any sign of RAID 0 or 1 providing higher performance than single drive operation. Is that all there is? Or can a different OS make the difference?
In Part 2, I'll exchange FreeBSD for Linux and find that not all open source distros are equal—at least when it comes to building NASes!