System Settings Part#2

This page provides information about the model, size, and the current status of all installed HDDs. From here, you can format and check the HDDs, and choose the RAID level that suits your needs. The TS-421 supports the following RAID levels with four HDDs installed: RAID 0, RAID 1, RAID 5, RAID 6, and RAID 10. You can also configure the HDDs in JBOD (Just a Bunch of Disks), where all HDDs are seen as one big drive. The best options are RAID 5 (at least three HDDs are required), which can tolerate the failure of one HDD, and RAID 6 (at least four HDDs are required), which can tolerate the failure of up to two HDDs.

The HDDs will be formatted and the synchronization process will begin once you select the RAID level. Synchronization will take a long time to finish, depending on the size of the HDDs you installed. Another significant option here is the Bitmap action because it improves the time it takes to rebuild RAID after an unexpected error, or when you remove or add a member HDD back to the RAID configuration. You can also perform other actions, like expanding the capacity of a RAID level or migrating, recovering, adding, or configuring a spare drive.


This group of options allows you to encrypt the contents of the drives with 256-bit AES encryption, configure the iSCSI (Internet Small Computer System Interface) service, and add iSCSI LUNs, with the latter being logical volumes mapped to the iSCSI's target(s). There is also a set of options for adding virtual disks. The TS-421 supports up to eight virtual disks.


The Network group gives you access to TCP/IP settings from where you can enable the two-NIC operating mode. You should enable the respective option to provide a higher bandwidth between the NAS and the switch if your Ethernet switch supports Link Aggregation. LACP does, of course, require two Ethernet cables for connectivity to both ports of the NAS. Another important setting here is Jumbo Frames, referring to Ethernet frames that are larger than 1500 bytes. The jumbo frames are designed to boost networking throughput and reduce CPU utilization on large file transfers by allowing larger payloads per packet. But there is a catch: The Jumbo Frame setting only applies to Gigabit network environments, and all connected clients must enable the option with exactly the same MTU value.

This subgroup of settings also allows you to set a DDNS Service that will give you the WAN IP, which would allow you to discover the NAS on the web if you don't have a static IP internet connection.


The Security group allows you to specify the IP address or the network domain from which connections to the NAS will be permitted or denied. You can also block an IP for a certain period of time or forever if the specific IP fails to login after a specified number of attempts. Finally, you can upload/download a secure certificate here.


These options allow you to configure the hardware functions of the NAS. The most important ones are the HDD standby mode option, the Write Cache option through which you can gain increased write performance, and the Smart Fan option which allows you to set the fan to auto mode or a customized fan profile.