Discussion on:

How SAS, Near Line (NL) SAS, and SATA disks compare

I'm looking at drives to buy for my first home server (it's a bare bones unit). I was thinking that if I'm going to spend this kind of money on it, I should go the extra mile and go for the best reliability I could get - my data is important to me. I hadn't heard of NL-SAS before and this article told me that's not the way I want to go.

Wouldnt an expander be a necessity to connect multiple disks to an initiator.I am confused

From wikipedia
An expander is not necessary to interface a SAS initiator and target but allows a single initiator to communicate with more SAS/SATA targets. A useful analogy: one can regard an expander as akin to a network switch in a network which allows multiple systems to be connected using a single switch port.

I wish I had known more about NL-SAS before I decided to purchase a new Dell server with NL-SAS drives -- to be used as a SQL server. I regret that decision -- even with only a dozen users hitting this server, the disk I/O is a real bottleneck. I will be sticking to SAS again from now on.

I'd like to point out that NL-SAS still gives you a full SAS electronics set including superior error correction and certified media plus a BER of 10^15 as pointed out in the article, but this still exceeds today's consumer sATA disks by a factor of 10 as consumer disks usually have a BER of 1 in 10^*14*.
Do the math on the probability of an unrecoverable error during a raid resync on let's say 6x2TB raid5/z1.
While 10^15 is available on sATA if you search for it with the price charged for such drives it simply does not make sense to go for NL right away.
Different story with raid6/z2.
Still the better option for reliable data tombs is consumer disks on raid 5 and regular backups to a jbod made of TB range disks.