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January 26th, 2014 15:00
What is the maximum throughput of PERC 5/E + MD1000? Confused in calculations.
Hello, I've read many articles about PERC 5/E and after last article from Dell's website I am totally confused. I do not have much experience with these things.
http://www.dell.com/downloads/global/power/ps3q07-20070368-Olivarez-OE.pdf
My question is: If I daisy chain 3x MD1000 and connect them to one port, what is the maximum throughput? How could I hit 1GBps? Is 300MBps maximum per port (wide port?) or per PERC 5/E? How could I go above this?
(on link provided at the top) "The PERC 5 is connected to the server through an x8 PCI Express slot rated at 2 GB/sec (although some systems may utilize an x4 PCI Express slot, rated at 1 GB/sec). The PERC 5 has two SAS wide ports to connect the controller to expanders. Each wide port is a combination of four SAS ports rated at 300 MB/sec each, providing a throughput of 1,200 MB/sec per expander, or 2,400 MB/sec total."
I understand wide ports, but what do they exactly mean by "four SAS ports" ?
Do they mean that each physical port is somehow 4 SAS ports? So it has dual x4 SAS? Then each port has throughput of 1.2GBps? Did I understand it correctly?
Please explain someone simply. Thanks in advance!
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Daniel My
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6.2K Posts
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January 26th, 2014 16:00
Hello
It would be 1.2GB/s. The PERC 5e has two connectors for two different channels. Each of those connectors consists of 4x300MB/s ports, so each channel is capable of 1.2GB/s. That is theoretical. You will not actually be able to hit that number as there is overhead to consider. The document states 80% is about the max achievable, so that would put you at around 960MB/s.
These are logical ports. That connector is for a channel. The channel consists of 4 logical ports.
Yes, that is basically what it means.
Thanks
DELL-Sam L
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January 27th, 2014 11:00
Hello ZippoWindproof,
To measure through put you need to measure the IOPS on your virtual disk. Knowing what the max that the HBA can handle is good but you really need to look at the IOPS to know if you have a true performance issue or not. We don’t have a tool that does measure IOPS but you can do a search & find IOmeter & they have a free tool that you can download and you can use that to measure the throughput of data to the MD1000.
Please let us know if you have any other questions.
ZippoWindproof
17 Posts
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January 26th, 2014 17:00
Thank you for your time!
This is what I wanted to know.
ZippoWindproof
17 Posts
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January 26th, 2014 18:00
Btw. does there exist some tool to monitor actual throughput by perc 5e?
Daniel My
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6.2K Posts
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January 26th, 2014 19:00
Modular disk storage manager is the only utility I can think of that does something like that, but it is only for the managed storage units like the 3000/3200. I'll ask Sam to look at this when he gets in tomorrow to be sure.
Thanks