Randomly looking at stuff on amazon. I came across this sever and I was trying to figure out if it was a good deal or not. Dell-R620
Also I looked at the raid card and noticed the spec sheet says it can control up to 32 devices but how can it do that with only 2 mini sas connectors?
SAS is a serial bus, and each device on the bus is assigned an address by the processor. So this unit’s processor can handle upto 32 devices. The two connectors likely provide four six-gigabit lanes each, for a total of 48 gigabits of bandwidth. Plenty for 32 mechanical hard drives.
Regarding the server, I would not recommend. 1st gen 5 series xeon are rather poor on the performance to watt ratio. If they were 2670v4 at that price, jump on it. 2670v3 maybe even still relevant.
Not a good deal at all, i just picked up a Dell R720xd for $350, that system holds 12 3.5 drives.
here is a good place to look up deals on servers https://www.labgopher.com/servers/Dell_R620/
Thank you for the info.
there must be a bus with more connections inside the chassis, the mini sas cables I find only have 4 connections on them, LINK
That cable is to attach sata drives to a SAS controller. SATA doesn’t support device addressing, so each channel can only handle one drive, without help from extra chips.
Like Gordonthree says, each SAS port typically connects to four drives, either with a breakout SAS or SATA cables, or to a backplane (HDD cage circuit board.)
The backplane acts as either a dumb distributor for the drives, or the backplane might already have an expander built in to them, so require less add on cards for many drives.
But, if the SAS controller supports many drives (32 and more is common) despite only having one- two- or four- SAS sockets, you can use a normal SAS-to-SAS cable from the controller to an expander, and daisy chain the connections.
You can get Some information about SAS expanders here
The article does mention about shared bandwidth, which only really concerns SSD’s.
But basically it can take one cable in, and split That or to four cables, each with four drives on.
You technically could use all four of those to each connect to an expander, and connect to 64 drives, but that would be silly.
It might be interesting to research SAS expanders, daisy chaining SAS, and just SAS in general.
But at the end of the day, as people already mentioned, the R620 is not a great deal, so maybe keep browsing while you research?
@Trooper_ish the information you provided is very much along the lines of what i was looking for. I am not so much looking to buy anything but always happy to learn. Thank you. 
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