As noted earlier, backup to attached USB / eSATA drives still isn't available for the N5500. I now know that rsync is at the heart of all NAS-to-NAS backup features. But since the N5500 "Nsync" interface only lets you enter the IP address of the target server and not a folder or module name, I couldn't try a backup to one of my rsync targets.
And although I managed to get "Legacy FTP" backup working to the N7700, I couldn't get the N5500 to find the nsync directory on the target FTP server that it was looking for. And there were no clues to be found in the 5500's log or in the log of the ReadyNAS NV+ that was the target. So Thecus still has a way to go in improving its NAS' ability to play nice with other products when it comes to backup.
The N5500 was tested with our standard NAS test process with 3.00.01 firmware and three WDC WD1600AAJS-0 160 GB Caviar Blue and two Seagate ST380815AS 80 GB 7200.10 drives that Thecus provided. Tests were run with 1000 Mbps and 1000 Mbps w/ 4K jumbo frame LAN connections.
I used all five drives in the RAID 0 and 5 tests, with EXT3 format and default 64 KB block size. The RAID wizard wouldn't let me put five drives into a RAID 10 array, so I used only the first four drives for that array, formatted in EXT3 with the 64 KB block size.
After some pokes from readers, I'm going to try to do a better job of documenting RAID array build and sync times. For both a 290 GB 5 drive RAID 5 and 145 GB 4 drive RAID 10 array, it took about 65 minutes from the creation of the array to when it was fully sync'd and pronounced healthy.
Figure 8 presents a summary of the write benchmark tests run for the N5500. There is some moderate cache boost for files up to around 256 MB. Write performance with a 1000 Mbps LAN connection averaged over the 32 MB to 4 GB file sizes and with cached results above 125 MB/s removed from the average measured 73.6, 54.5 and 66.8 MB/s for RAID 0, 5 and 10 writes, respectively. RAID 0 and 10 speeds stay relatively flat from 512 MB file size on up, with RAID 5 falling off as file sizes grow.
Figure 8: Performance benchmark summary - write
Figure 9 shows the average read performance for the same test configurations which came in higher at 70.2, 63.5 and 67.8 MB/s for RAID 0, 5 and 10, respectively. Performance is evenly matched up to the 256 MB file size point. From there on, RAID 0 holds up the best, followed by RAID 10, then RAID 5.