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2005-10-17 17:23:22
Requirements for RAID-5 volumes:
1,a RAID-5 volume must consist of at least three components. the more components a RAID-5 volume contains, however, the longer read and write operation take when a component fails.
2,RAID-5 volumes cannot be striped, comcatenated, ormirrored
3,do not create a RAID-5 volume from a component that contains an existing file system. doing so will erase the data during the RAID-5 initialization process
4,when you create a RAID-5 volume, you can define the interlace value. if not specified, the interlace value defaults to 16 Kbytes. this value is reasonable for most applications
5,a RAID-5 volume can only handle a single component failure
6,when you create RAID-5 volumes, use components across separate controllers. controllers and associated cables tend to fail more often than disks
7,use components of the same size. creating a RAID-5 volume with components of different sizes results in unused disk space
The following table explains RAID-5 volume status:
1,initializing:slices are in the process of having all disk blocks zeroed. this process is necessary due to the nature of RAID-5 volumes with respect to data and parity interlace striping
. Once the state changes to 'Okey', the initialization process is complete and you are able to open the device. Until then, application receive error messages
2,Okey:the device is ready for use and is currently free from errors
3,Maintenance:a slice has been marked as failed due to I/O or open errors. these errors were encountered during a read or write operation
