Linksys NSS2000 Cisco NSS2000 Series Network Storage System Administration Gui - Page 175

Glossary of Storage-Related Terms & Acronyms B M MDFS (Microsoft Distributed Filesystem): see DFS. Mirroring: For NAS devices, the automated process of simultaneously writing data to two (or more) hard disk drives. Mirroring creates a redundant repository of data, such that if one of the hard disk drives (HDD) fails, the redundant drive continues to provide access to the stored data for connected users. Network administrators can then replace the failed drive with a new drive that can be re-mirrored to the good drive. RAID level 1 uses mirroring. MTBF (Mean Time Between Failures): A measurement of hardware product reliability typically indicated in thousands, tens of thousands, or hundreds of thousands of operational hours between failures. It is most often defined as the average time between failures. MTBF can be derived from extensive and time intensive testing of the working product, calculated from actual product field performance (depending on the product, its market, its usage, and the ability to retrieve accurate usage data), or from a calculated prediction based on known factors. Manufacturers provide MTBF as a reference of the product's, or its subcomponent's reliability. Customers can use the MTBF to determine their service needs to maintain or replace the product. Cisco Small Business NSS2000 Series Administration Guide 167