wlm2005 Posted July 8, 2007 Share Posted July 8, 2007 First let me say, I have unRaid up and running, and I love it. But I do have a question. I have 4 sata II ports on board. When I was setting it up and running the parity check, it runs very fast. But I know I will need more ports so I bought the PROMISE SATA300 TX4 PCI SATA II Controller Card, switched my 4 500 gig drives over to it (wanted to try it out), But then my speed on parity was cut in half. So my question are: 1. Is it just my parity drive its effecting or is it going to cut all my transfer speeds in half? 2. Will it maintain its fast speed if I keep the parity drive ported to the motherboard. I guess what I am saying is, are the drives ported to the motherboard going to faster then the drives ported to the controller card, and will it be noticeable on reads and writes?? Sorry, I hope this makes sense, I had a hell of a time trying to word this right. Link to comment
Joe L. Posted July 8, 2007 Share Posted July 8, 2007 First let me say, I have unRaid up and running, and I love it. But I do have a question. I have 4 sata II ports on board. When I was setting it up and running the parity check, it runs very fast. But I know I will need more ports so I bought the PROMISE SATA300 TX4 PCI SATA II Controller Card, switched my 4 500 gig drives over to it (wanted to try it out), But then my speed on parity was cut in half. So my question are: 1. Is it just my parity drive its effecting or is it going to cut all my transfer speeds in half? 2. Will it maintain its fast speed if I keep the parity drive ported to the motherboard. I guess what I am saying is, are the drives ported to the motherboard going to faster then the drives ported to the controller card, and will it be noticeable on reads and writes?? Sorry, I hope this makes sense, I had a hell of a time trying to word this right. It sounds like the controller on the motherboard is faster than the Promise SATA300. (assuming you had the same drives connected to both) If you added additional drives, then it will be slower, regardless of which controller they are connected to. If the two controllers do not have to share the same bus, it will be faster than if they share the same bus on the motherboard. What speeds are you seeing? Link to comment
wlm2005 Posted July 8, 2007 Author Share Posted July 8, 2007 It sounds like the controller on the motherboard is faster than the Promise SATA300. (assuming you had the same drives connected to both) If you added additional drives, then it will be slower, regardless of which controller they are connected to. If the two controllers do not have to share the same bus, it will be faster than if they share the same bus on the motherboard. What speeds are you seeing? Joe L. Thanks for the reply.. I'm doing a parity check right now and I am getting (55,534 KB/sec). When I port out of the Promise SATA300 card it will drop to around (24,000 KB/sec). Bill Link to comment
cmhardwick Posted July 9, 2007 Share Posted July 9, 2007 I run my parity drive on the onboard SATA connector and my 3 data drives (2 750 and 1 320) on my promise TX4 and I get around 50,000 parity speed. So I know it will work that way, but can't offer any insight sorry. Link to comment
limetech Posted July 9, 2007 Share Posted July 9, 2007 What's happening is the PCI bus at approx. 133MB/sec becomes the bottleneck. The parity sync rate is showing the rate at which the parity drive is being written. To generate/check parity you have read all the data drives, and write (or read) the parity drive. So 133MB/sec PCI bandwidth divided by 4 (because all 4 drives share the PCI bus) is about what you should see. Link to comment
cmhardwick Posted July 10, 2007 Share Posted July 10, 2007 So it seems a good thing to put your parity drive on a different bus, as I did, by putting it on the MB. I'll probably see a hit more from adding drives than the PCI bottleneck, correct? Link to comment
wlm2005 Posted July 10, 2007 Author Share Posted July 10, 2007 What's happening is the PCI bus at approx. 133MB/sec becomes the bottleneck. The parity sync rate is showing the rate at which the parity drive is being written. To generate/check parity you have read all the data drives, and write (or read) the parity drive. So 133MB/sec PCI bandwidth divided by 4 (because all 4 drives share the PCI bus) is about what you should see. I have more drives coming this weekend. I am going to put the parity and some others on the MB and some on the controller card. just to see what happens. As long as parity is fast is the main thing, right?? Link to comment
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