[rescue] Sun Blade 100 Question - IDE

[James Lockwood]

On Fri, 10 May 2002, Big Endian wrote:

> The issue is the IDE bus config.  If you have two devices on an IDE
> channel, you get a significant performance hit on that bus.  I've
> seen numbers up to a 40% hit if you have two hard disks on the same
> bus.

It's even worse than that.  If you have two devices on an IDE channel and
one fails, it will usually prevent the other one from functioning normally
while the first one is still attached to the bus.

This means that RAID1 on two drives on a single bus is an exceptionally
bad idea.

_All_ forms of RAID present potential performance hits.  Some present
performance benefits.  It's possible for striping to drop performance
depending on the I/O size mix and the stripe size.  Mirroring will
generally lower performance on writes and slightly increase performance on
reads.

-James