To simulate disk failure on a fully synchronized RAID 10 array, I pulled the SATA cable from disk3 with the system powered down, and turned it back on to see how it would respond. With the boot sequence complete, the SYS LED on the front of the NSA was blinking red. However, the ALARM LED for disk3's drive bay was not lit.
File shares and data were still on line and accessible, the volume's capacity was unchanged, but the admin screens indicated a problem with the volume. Figure 15 shows volume1 is "Degraded" and the Disk display shows disk1, disk2, and disk4 healthy, while disk3 is absent.
Figure 15: Disk Status showing volume Degraded
In addition to the above, the system log reported a Critical message stating, "There is a volume degraded." This same message was also immediately emailed to the address configured in the Maintenance menu.
Turning the system off, reconnecting the drive, and powering back on resulted in the SYS LED going green, with the DIAG LED now blinking red, and additional messages of "There is a volume degraded." Again, the system was on line and accessible, this time with the admin screen reporting volume1 as "Recovering."
Figure 16 shows volume1 has changed from "Degraded" to "Recovering," and all four disks report as "Healthy." The "Recovering" process for this RAID 10 array took 138 minutes before the system was at a normal status as indicated by the DIAG LED going out, volume1 showing "Healthy," and a System Log entry of "RAID Recover completed." During this process, I noted that the data on the drive remained intact and available.
Figure 16: Disk Status showing Recovering
The following morning, the daily status report indicated there had been two "volume degraded" events, and noted their time and date.
We ran ZyXEL’s storage appliance through our NAS file system performance tests, and you can find it listed in the NAS charts. I've pulled some data from those charts to highlight its functionality, and look at how the NSA-2400 stacks up against other NASes we've recently reviewed.
- Firmware version: V2.11(AFA.0)C0 08/09/07
- Maximum raw data rate for 100Mbps Ethernet is 12500 KBytes/sec (12.5 MBytes/sec) and 125000 KBytes/sec (125 MBytes/sec) for Gigabit.
- Full test setup and methodology are described here.
Figure 17 shows the NSA-2400's 100 Mbps Ethernet and gigabit Write performance. It is no surprise that gigabit performance exceeds 100 Mbps Ethernet performance in all configurations. Further, this chart shows that the NSA-2400's Gigabit RAID 10 array has better Write performance than its Gigabit RAID 5 array at 64M, 128M and 1G file sizes.
Figure 18 shows the NSA-2400's 100 Mbps Ethernet and gigabit Read performance. In this case, its gigabit RAID 10 Average Read performance is above its gigabit RAID 5 Average Read performance at all file sizes.