[Techtalk] Made RAID Mistake?

[Kelly Martin]

Andrew wrote:

> 	I read a theory piece that questioned the need for hardware Raid now that 
> 100,133 and SCSI 160MHz are available on the board or with less expensive 
> non-raid cards. Using intelligent partitioning, LVM and maybe software raid 
> should give satisfactory results. 
> 	I am interested in opinions of the experienced people here. Maybe I am 
> missing part of the concept?

Software RAID is virtually always a performance loss over hardware RAID. 
  No matter how you slice it, more of your processor AND I/O bus will be 
taken up doing the redundant I/O that is required for RAID.  Unless your 
system is so lightly loaded that you can afford this increase in I/O and 
processor utilization, your performance will be impaired.  Also, 
software RAID is less likely than hardware RAID to be able to 
parallelize the I/O operations, so overall performance will be lower.

I can't see how any software system can even theoretically yield the 
performance and reliability advantages of hardware RAID.

Kelly