Comment on Am I corrupting my data?
thelemonalex@lemmy.world 1 day agoThank you very much for the detailed information. I’ll look into eBay again, maybe I can find a good offer that works. I’m unsure how to choose the number of lanes. Does that relate to the number of drives it supports? Also, in terms of cooling, would any PC case fan be enough, if strapped onto the HBA?
Nollij@sopuli.xyz 1 day ago
Kind of. They will be multiples of 4. Let’s say you got a gigantic 8i8e card, albeit unlikely. That would (probably) have 2 internal and 2 external SAS connectors. Your standard breakout cables will split each one into 4 SATA cables (up to 16 SATA ports if you used all 4 SAS ports and breakout cables), each running at full (SAS) speed.
But what if you were running an enterprise file server with a hundred drives, as many of these once were? You can’t cram dozens of these cards into a server, there aren’t enough PCIe slots/lanes. Well, there are SAS expansion cards, which basically act as a splitter. They will share those 4 lanes, potentially creating a bottleneck. But this is where SAS and SATA speeds differ- these are SAS lanes, which are (probably) double what SATA can do. So with expanders, you could attach 8 SATA drives to every 4 SAS lanes and still run at full speed. And if you need capacity more than speed, expanders allow you to split those 4 lanes to 24 drives. These are typically built into the drive backplane/DAS.
thelemonalex@lemmy.world 10 hours ago
I see, okay, I understand now. Thank you very much for explaining that in detail!