Product data

Storage Concepts and Technologies
• Hardware based RAID array: Many other SMB and SOHO NAS devices run small
processors and software-based RAID. The result is transfer rates that average
10MByte/second, which is quite slow compared to what Linksys NSS systems offer
with a hardware based RAID array.
• Hot RAID Spare: A spare hard drive can be designated as a Hot Spare in the event of a
disk failure in the RAID set to provide maximum data protection.
• Journaled File System: Linksys NSS products utilize XFS, a journaled file system. A
fault-resilient file system provides data integrity because updates to directories and
bitmaps are constantly written to a serial log on disk before the original disk log is
updated. If the system fails, a full journaling file system restores the data on the disk to
its pre-crash configuration. It also recovers unsaved data and stores it in the location
where it would have gone if the computer had not crashed.
• Redundant LAN Connections: Dual Gigabit Ethernet (10/100/1000) links facilitate
export of virtualized RAID sets and backup operations.
• Staggered Drive Spin-UP: The NSS devices minimize system power supply cost by
using a single, sequential hard drive power up or power down in the storage array.
Drives are spun up one at a time to minimize spin-up power draw which, in other
arrays, can typically be 4 to 5 times the draw on power depending on the number of
drives in the array.
• Idle Drive Spin-Down: The NSS devices feature “Idle Drive Spin-Down,” which helps
to extend the lifespan of the disk drives. This minimizes active drive operation when
the NSS device is not being accessed, achieving stated “Mean Time Before Failure.”
• SNMP traps (gets only) can be sent to an SNMP-capable network management system.
The system also supports remote logging with syslog and system alerts on electrical
and mechanical anomalies should they occur (these alerts are visible in the
management GUI of the device).
• Optional External Redundant Power Supply and integrated UPS support: RPSU
support is available for NSS devices and the NSS can be connected to UPS products.
MTBF
Mean Time Between Failure (MTBF) is a storage performance metric. Linksys NSS devices
are designed to increase MTBF with the following capabilities:
• Environmental controls reduce the amount of power consumed (Stagger Drive Spin-
UP).
• When drives are not being used, the disks will spin-down to an idle state after some
period of time to prevent disk failure (Idle Drive Spin-Down). This increases drive
lifespan and saves power. The default spin-down time is set for 8 hours.
• NSS devices are designed to operate with best in class disk drives, which support a
business-class requirement for 7x24x365 operation (see Linksys Approved Vendor List
for recommended drive manufacturers).
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Note
MTBF is not an indicator for how long any particular drive will last and may not
necessarily represent storage performance in ‘real World’ usage. Accordingly, MTBF
should not be used as the only metric to assess storage performance. A backup strategy
should also be implemented to protect against any drive failure. Note also that use of
unsupported drives could result in unpredictable system behavior or data loss.
White Paper: Network Storage LINKSYS © 2007
23 EDCS-593805 v1.0
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