I used IOzone to test the file system performance on the 5big (the full testing setup and methodology are described on this page). I tested with 2.1.1 firmware in RAID 0, 5 and 10 modes with 100 Mbps, 1000 Mbps and 1000 Mbps w/ 4k jumbo frame LAN connections.
Figure 5 shows write benchmarks plotted for RAID 0, 5 and 10 with a 1000 Mbps, 4K jumbo frame LAN connection. Average throughput for the large file sizes from 32 MB to 1 GB measured 20, 16.9 and 21.8 MB/s respectively. You can see the performance boost that the combination of striping and mirroring used in RAID 10 provides over RAID 5.
Figure 5: Write benchmark comparison - 1000 Mbps, 4k jumbo
Figure 6 shows the read results for the same tests, with averages of 32.9, 27.9 and 28.4 MB/s recorded for RAID 0, 5 and 10. This time the overhead for RAID 5 and 10 is about the same, with both coming in slower than RAID 0.
Figure 6: Read benchmark comparison - 1000 Mbps, 4k jumbo
For RAID 5 write performance, Figure 7 shows that the 5big isn't in the same league as the other current crop of 5 drive NASes. The Thecus N5200 Pro, Synology DS508 and even the older Thecus N5200 all use more powerful Intel or Freescale general purpose processors than the 5big's Marvell "Orion" NAS SoC and have more memory.
Average write throughput for the 32 MB to 1 GB "large" file sizes measures 42.3, 40.9, 35.1 and 16.9 MB/s for the N5200 Pro, DS508, N5200 and 5big, respectively.
Figure 7: RAID 5 write competitive comparison - 1000 Mbps, 4k jumbo
Figure 8 shows a different story for reads, however, especially for larger file sizes, where performance tends to even out. Average throughput came in at 44.8, 33, 32.9 and 27.9 MB/s for the DS508, N5200 Pro, N5200 and 5big, respectively.
Figure 8: RAID 5 read competitive comparison - 1000 Mbps, 4k jumbo
Run your own comparisons using the NAS Charts.
The LaCie 5big has an odd mix of pluses and minues. While it strikes me as a more of a "business" than "consumer" NAS, it isn't really isn't a "best in class" offering for either market.
Where the 5big does shine, however, is in value. At around $750 it's the least expensive five drive NAS that you can currently buy and that includes 2.5 TB of storage! The Thecus N5200 and N5200 Pro, Synology DS508 and QNAP TS-509 Pro are all BYOD and (except for the N5200) are priced $100 to $200 higher.
So if throughput and media serving isn't a high priority and you're looking for a lot of Windows and Mac OS-friendly RAID 5, 6 or 10 storage for your money along with smooth and automatic drive failure recovery, the LaCie 5big could be worth a look.