Novell Open Enterprise Server 2 Manual De Usuario

Using Software RAID1 Devices for Data Fault Tolerance

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NetWare

®

 Traditional File System volumes can span multiple disks. If a single disk fails, all 

Traditional volumes that have segments on that disk also fail. To increase the data fault tolerance of 
a server that has a Traditional file system, you can mirror the data from a Traditional NetWare 
partition on one disk to Traditional NetWare partitions on other disks. 

This section discusses the following:

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Mirroring is a software RAID1 technique that writes data in parallel to multiple separate devices. If 
one device fails, the other member devices remain available. 

You can create a software RAID1 device with up to four member partitions, including the original 
partition and up to three mirrored partitions. Each member partition resides on a separate server 
disk. 

As contrasted to a hardware RAID1 device, the server operating system controls the mirroring 
activity in a software RAID1 device, which can slightly impact the CPU performance for the server. 
Adding additional mirrors after the first contributes to availability, but it also incrementally impacts 
CPU performance.

Typically, you write only to the original partition and send duplicate writes to the mirrored 
partitions. However, you can read from all member partitions. This improves the read performance 
of your Traditional volumes that contain volume segments in member partitions of the RAID.

This section discusses the following considerations for achieving fault tolerance:

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If you mirror one partition, you do not necessarily provide data protection for the entire volume. To 
create software RAID1 devices for Traditional NetWare partitions, you must keep in mind the 
relationship between Traditional NetWare partitions, volumes, and volume segments. (For 
information about these key concepts, see 

.)