RAID what?

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Originally Posted by D_o_S

Um... I'm using 2 6800 Ultras in SLI ;)

I can't get Areca.... so should I go for Adaptec? What about High Point?

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if you can't go PCIe
and are going eitheir PCI or PCI-X, get Adaptec.

i would think that the integrated controller would be better then one running on a regular pci bus am i wrong?

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Originally Posted by brandinb

i would think that the integrated controller would be better then one running on a regular pci bus am i wrong?

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I used to think that also. I guess it pretty much will vary from computer to computer you know?

So far some of these cards are boasting about 200% increase over onboard based SATA/RAID controllers. Too bad they aren't cheaper...which makes the onboard stuff more ideal...:stick:

Its only for 4 drive arrays you'll see that boost over the integrated RAID (lol, its really software RAID which for most things sucks). For 2 drive RAID 0 you can actually get fairly close to the performance of these hardware controllers. Only for RAID 0 and 1 though, if you want to do something like 0+1 or RAID 5 those integrated controllers offer truly abysmal performance, I've seen some people get around 5MB/s with em'...

Yea, those prices for the hardware cards looks pretty scary at first, but you gotta remember that you can use em' across mult. machines over the years the cost gets spread out. Well worth it IMO as I plan to use my Areca card for at least 4 years or so before it gets sold off or used to build a backup house server or something.

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Originally Posted by vitaminc

1) You quoted the beginning of RAID but not end of RAID, which would be a lot lower. What's more important is the average STR thoughout the whole HDD, not the STR at the beginning of the disk (fastest part).
2) Software RAID0 results in 40+% CPU utilization.
3) FreeBSD instead of WinXP. Two different file systems. Minor impact on benchmarks.

To quote from that bench:


Always wonder why people expect any decent performance with integrated RAID controllers when they know stand alone gfx card will always beat the integrated chipset video solutions.

Reasons why not to use RAID0 beyond 2 drives:
1) random accesss time will increase as you add more drives to your array (duh)
2) incremental burst read speed will decrease as you add more drives
3) sequential transfer rate scales the best with RAID0, but will also decrease incrementally due to packet overheads.

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I quoted the beginning of the disk, because anyone with a brain will place partitions that hold large contiguously read/written files at the beginning of the disk.

The 40% CPU at that speed is mostly filesystem and controller driver, it has nothing to do with the software raid. A hardware raid won't have any lower CPU utilization here.

As for reason 1) of yours: clearly the random read access time stays the same for me with increasing number of drives, I don't know where you would see a possible slowdown. If you do some simultaneous writes things look even better.

Reason 2), I don't know what you call an "incremental burst read", if it is what the choice of words might imply, then this is something that the OS/filesystem's readahead functionality takes care of. It has nothing to do with the disk controller, disk, or RAID.

Reason 3): paket overhead?