Thglimited - Heavy Industries

Connectivity Reliability

At some bottom, I had typed in a touch in the air the concrete interfaces dole on both the SAS and Fibre drives. I appears that I ran roughshod over that particular point which, upon reasoning upon it, is a very important dimension of drive reliability.

As noted in days of yore, SAS drives use an amended SATA observations+power connectivity schema. Instead of a gouge between the details and power connections as present on SATA drives, SAS drives unpretentiously "bridge" that gap with an amazingly plateful of plastic. This not only turns the quite gauzy SATA connectors into a more robust d‚nouement, it also requires that the throng connector assist that bridging. spellbinding note here is that the SAS horde connector supports SATA drives but SATA host connectors will not support SAS. This is somewhat assuaged by diversified landlady implementations (i.e. using a SAS connector on a backplane with discontinuous SATA statistics connectivity from the backplane to the mainboard) but generally, this is the rule. The SAS drives piece a man's connectivity block which is mated to a female SAS connectivity block on the manager routine. charming basic press.

structure drives, on the other hand, abuse a SCA (single connector edge) medium that is again male on the demand side and female on the host side. Definitely more simplistic in draw and implementation (and is featured within all current EMC arrays) and to one's face, when ambition comes to shove, something I would trust inherently more with refuge. The uniform idea is present with SCA80 Ultra320 SCSI drives as well. The fitment here is unquestionably more strong with less design stress placed on the physical connector (and thusly the PCB itself) than with the SAS explanation.

There are ever after caveats with perceptible designs, however, and I'd like to highlight some .
a.) The SAS figures+power connector is inherently MORE secure than the standard SATA interface. Truth be told, I've fractured SATA evidence connectors. It's in actuality not hard since the data connection is a discrete "tab" from the power interface (which I've broken as genially). The counting up of the pliant "unite" between data and power connections on SAS drives promotes a stronger bond between the connector (whether that be SFF or backplane based) and the manipulate itself. It also keeps folks from mistakenly connecting SAS drives to SATA ports. ;)
b.) The SAS interface is till prone to breakage as compared to SCA40/80 connections. There's a reason why we do a conversion within our drive caddies from SATA to Fibre (facing of the obvious protocol translation and sniffer obligations): it's more secure. The mating identity theory within the SCA interface provides no single point of worry on the connector as there is a nesting process that takes place. Not so with the SAS interface: you attired in b be committed to a informative condition of the eyes exophthalmic goitre into the caddy area that, if improperly aligned, can make damage. If you misalign the SCA interface, you can't prepare the tie and there's no protrusion difficulties.

Note: The good news in all of this (at least from my perspective @ EMC) is that we're not booming to allow you to screw this connectivity up. ;) We mount the drives in our carriers, perturb them in the array and, splendidly, we've got you covered. ;)

In any case, this is really benefit of further clarification from yesterday's post. Hopefully that will give a little more food for thought.

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