James wrote regarding 'Re: [SLE] Mail Server purchasing decision' on Fri, Sep 03 at 08:44:
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On Friday 03 September 2004 9:57 am, Joe Polk wrote:
I would agree with many of your points save one. HW RAID (not including Promise IDE stuff because that's not a true HW controller in the same sense that a Compaq SMART Array Controller is) is always going to be faster. There is no way, for instance, SW RAID could compete with say a 6400 w/256MB Cache Module.
You really should look at http://spamaps.org/raidtests.php
They used the 3ware controller in both tests, using the 3ware controller's on-board cache in both cases. What kind of person is gonna buy a RAID controller and then run each disk on the controller individually, using software RAID instead of the hardware raid that they paid for? If those disks had been on the motherboard IDE interface, like >99% of people who use software RAID, the software RAID would've lost, but it does show where a little ore performance could be gained *if* CPU load is irrelevent. What happens when the CPU starts getting loaded down, too, like on a busy database, mail, or web server? Hint, the hardware RAID card keeps up, while software RAID degrades. With software raid, you also don't get the fancy management interface that most of the big names provide for their cards. Everyone loves a web interface! :) Anyway, I much prefer having the processor left as free as possible for dealing with processing, not wasting time handling I/O stuff that dedicated hardware can do just as well or better in real-world use. Feel free to disagree. --Danny