Well drat. I got 8 copies of the CPU 3/4 heatsinks so I won't be firing mine up tonight. Emailing Justin instead....
My c6145s came with only CPU 1/2 style heatsinks, but Justin later sent me right right number of 3/4s to make it right. He may be able to send you your 1/2s.
Now if he does not have the right heatsinks, let me know. He didn't want the 1/2s back, so I have extras and can swap with you.
Did your c6145 come with plastic airflow baffles? If not then there really isn't any reason to use two different types of heatsinks anyway. Until you get your heatsinks sorted, you can use a driver to remove the little pins that enforce heatsink placement. It takes just a minute or two to remove them - and to put them back in place.
He's got the 1/2s shipping out today. That is some fantastic service!
I don't see any baffles inside the box, but then again, I probably wouldn't know them from something else
Do you have any idea what expander chipset is used? It's possible that the expander only negotiates SATA-II speeds for sata drives but can run at the full link speed with SAS. Other SAS expanders with non-LSI chipsets (like the HPs) have this behavior.
I don't think it could be the drive links. With twelve drives, even SATA 1 speeds of 125MB/S would yield 1.5GB/S in aggregate - far higher than I'm seeing. It must be the connection between the backplane and the LSI card which I note is nearly exactly 4x250MB/S, the real-world throughput of a SATA2 connection. My next step is to put that LSI 9201-8i into another machine to see if it can do 6Gb/s or is limited for some unfathomable reason to 3Gb/s.
24-bay Expander board details and performance:
My c6145s - and probably most of the 24-bay c6145s sold - include a SAS/SATA expander board attached to the disk backplane. I like the concept - twelve drives per motherboard but only one fat SAS connection to deal with. It works as advertised, but so far its performance does not impress.
Physically, the expander is a large circuit board that plugs in to the disk backplane via a PCIe-style connector that appears to be used for power only. Aside from this PCIe connector, the expander board has six SFF-8087 ports for disks and three SFF-8087 ports for the two c6145 motheboards. Oddly, one motherboard gets one SFF-8087 port while the other motherboard gets two, so one system will get four channels while the other will get eight - although the motherboard sled can only handle six. I would have expected a 6+6 arrangement, but the expander electronics probably made this impossible.
The six disk ports on the expander board each connect to four hard drives on the disk backplane via a SFF-8087 to single SAS/SATA breakout cable between the expander and the disk backplane - six such cables in total.
So the entire disk IO path looks like this: Disk drive with its sas/sata connector --> disk backplane board --> backplane to expander cable --> Expander board --> Expander to midplane cable --> Midplane board --> Motherboard sled board --> motherboard disk cable --> SAS Card.
While the "slow" motherboard gets only four 6GB/S SAS channels, that shouldn't be a big problem because we can expect 2GB/S worth of throughput from those four channels. Let's test and see.
I connected 12 Samsung 840 pro 128GB SSD drives to motherboard 2 and formatted them as separate drives. I then ran IOMeter with four workers testing 1MB random reads with a queue depth of 32. What I expected to see is 2GB/Second, limited by the performance of the single SAS x4 connection to the expander. What I actually saw was 1GB/Second - 983MB/S to be more exact. This is suspiciously close to the throughput limit for a SAS 3Gbit x4 connection, so I wonder if the c6145 expander is 3GB/S only or - more likely - if my LSI card is acting up. The card is a new-to-me LSI 9201-8i that is SAS2008-based and looks like a 9211-8i but does not exist on the LSI web site.
I'll probably have more information later, and since I'm seeking throughput, I'll probably end up re-wiring the c6145 to bypass the expander entirely.
Do you have any idea what expander chipset is used? It's possible that the expander only negotiates SATA-II speeds for sata drives but can run at the full link speed with SAS. Other SAS expanders with non-LSI chipsets (like the HPs) have this behavior.
They're in the unfinished part of the basement (aka, I can't hear them from the office area), but when I poke my head in, they don't sound like they're running full tilt (i.e. as fast as they did after a cold boot), but then again, there's also a Supermicro 2042-G running in the same rack that is a bit whiney.That's pretty disappointing. With only 1 node running it really should not be throttling... Are the fans going full tilt during your testing?
Looks like this thread kinda went quiet for a bit.
hey dba
I am curious about the performance issues on this C6145 ... does it still have "sub par" performance for its hardware spec, or did you guys figure something out that brought it to what you were expecting originally?
I am looking around for documentation on the servers EOL to guess when dell plans to sell it to the secondary market.
When these things drop in price like the C6100 did, I would love to get my hands on one...but I was not sure if you are determined its efficiency and cost-effectiveness aren't really worth it?