NetWare Disk Mirroring: The Poor Man's Approach to Hard Drive Redundancy
Articles and Tips: tip
01 Oct 1998
A critical part of maintaining a stable server is to have a reliable disk subsystem. In the early days of PC hardware, hard disks were notoriously prone to failure. To increase the reliability of NetWare servers, Novell has included a basic disk mirroring capability in all versions of NetWare since version 2.x. Disk mirroring maintains the same data on two separate disks. If one disk fails, the operating system instantaneously switches over to the other disk without any server downtime.
Nowadays, the ultimate in hard disk reliability is the use of RAID (Redundant Array of Inexpensive/Individual Disks), which has fault tolerance and redundancy built in to the hardware. Over the years, the increasing popularity of RAID solutions has relegated software mirroring to a rarely-used option. Yet as network servers require more and more disk space, the associated costs for RAID systems can increase dramatically.
Fortunately, you can still use NetWare's possible to get the protection of hard disk redundancy without the cost of RAID. Disk mirroring is still a viable option in the NetWare installation utility. You don't have to use the same brand or size of hard disks, but they must have the same number of blocks, which may reduce the usable disk space on the larger drive if you mirror two disks of unequal size.
* Originally published in Novell AppNotes
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