Gentoo Archives: gentoo-sparc

From: Derek Pizzagoni <pizz@×××××××.net>
To: gentoo-sparc@l.g.o
Subject: [gentoo-sparc] RAID-1 Question
Date: Fri, 26 Aug 2005 17:59:08
This is not necessarily sparc-specific, but I'm running Linux on my
Ultra10, so I figure it can't hurt...

If you run RAID-1, where one of the members of a mirror is running at
ATA-33, and the other member is running at UDMA-100, what type of
performance can you expect?

I know that when you write, you'll write to both, which means you still
have to write at UDMA-100 and ATA-33 speeds, but when you read, what
happens?  Is the driver smart enough to read from the faster drive?
Does it probe both, and whichever one responds first gets it?

Obviously, it would be best to run them both at the same (and highest)
speed, but you're limited in the number of drives that can fit inside
the case of the Ultra10.  I'm considering booting off of the internal
IDE, and running the rest of the system off drives connected to a
higher-speed PCI-IDE card.  The problem is, I haven't found an easy way
to put 3 hard disks inside (I just can't seem to get a drive to fit
above the floppy...), unless I get rid of the CDROM drive.

I've considered SCSI, but the drives are just too expensive, and the
higher-end IDE drives out these days are pretty fast.

Thanks in advance...
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