December 23, 200817 yr Several weeks ago I struggled with random DMA errors when performing I/O operations to my disks. It took me a while, but eventually I did figure out the root cause. I had two different "Y" splitters that were making intermittant contact with the molex connectors in the drive trays. These have been in my server for 3 years, and have not caused me any problems, but lately I've been shuffling a lot of different drives in and out of the case, and I guess that in combination with the increased power draw and vibrations from heavily used disks just allowed the problem to show itself. I know the splitters are very low-tech, but the originals in my server were not very large gauge wire, and very light-weight pins compared to the ones I picked up to replace them. I was actually able to hear the disks load and unload the heads as I moved the old "Y" splitter cable. At first I thought it was only one defective splitter and I replaced it. Then a second error occurred on a different disk in the other half of the server case. It was a second bad splitter in the top half of my case, and on the other power supply. (I have a dual supply configuration) As part of my attempt to isolate the trouble I had unplugged everything but the essentials, so my cuttng the tie-wraps on the upper power cables allowed the intermittent to show itself there too. The old splitters were 2 way. The new are 4 way. In the picture below new 4 way splitters are on the left... they are much higher quality construction than the two way splitters I removed from the server on the right. I have a feeling the crimps on the pins of the old splitter's connectors are of poor quality, and intermittent... Search here for what I purchased: http://www.intrex.com/parts/parts.aspx This is the part number: ADA-POWYX2 Very decent for $2.99 each. There are two Intrex stores iin my local area, so it is easy to stop by for parts... Besides working better, the new splitters prevent "hair loss" * Joe L. (* Now that the server is working properly once more, I can stop pulling out my hair trying to find the cause of the DMA errors)
July 11, 201411 yr Those look pretty nice, but the part number doesnt come up on their website. This is a 6-year-old link !! ... so it's not surprising it no longer is valid. You can see what Intrex currently offers by going here: http://www.intrex.com/parts/parts.aspx Then pointing to Power on the left side and selecting "Power Cables". They no longer offer a molex splitter, but do have a SATA power splitter (which is more likely needed with modern systems). I've not had any problems with the molex splitters sold by MonoPrice, although they are very inexpensive and do you do have to be sure the pins are correctly seated. http://www.monoprice.com/Search/Index?keyword=molex+splitter
July 11, 201411 yr Those look pretty nice, but the part number doesnt come up on their website. This is a 6-year-old link !! ... so it's not surprising it no longer is valid. You can see what Intrex currently offers by going here: http://www.intrex.com/parts/parts.aspx Then pointing to Power on the left side and selecting "Power Cables". They no longer offer a molex splitter, but do have a SATA power splitter (which is more likely needed with modern systems). I've not had any problems with the molex splitters sold by MonoPrice, although they are very inexpensive and do you do have to be sure the pins are correctly seated. http://www.monoprice.com/Search/Index?keyword=molex+splitter Doh! Im an idiot! I guess the spam caused it to be a "new post".
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