Confusion about external storage

T

tombew

Limp Gawd
Joined
Jan 5, 2005
Messages
232
I am confused over adding a "storage box" that connects to my main computer.
extenders, port replicators, backplanes, etc. Do I need a motherboard w/OS installed?

I have 10 x 3TB SATA3 drives + 6x 2TB SATA2 that I would like to connect to a system as JBOD, with the ability to add more drives later.
RAID 6 not essential at this time, but if not crazy expensive, would be good.

Is there a guide somewhere that explains my options to do this?

I can see that something like a Norco C-24U or NORCO RPC-4220 can hold the drives, but then I get lost over exactly how they connect to a RAID card.

If someone wants to recommend specific equipment, it would help me figure this all out.
 
The RPC-4220 is just a case. You need a motherboard/CPU/Ram/OS to set this up as a file server. It'd connect to your network and show up as a network drive. There are RAID cards with that many ports from Adaptec or LSI, but they are in the $800-$1000 range. The backplane is just what the hard drives connect to.
 
Thanks for the reply, but I am interested in doing this without going thru a network.
I am under the impression I can connect a RAID card to a RPC-4020, but that is where my confusion starts.
Any URL's anyone might suggest to learn about this?
 
If you wanted to use the RPC-4020 as an external storage box you would need to add a few things to it to make it work externally to your main computer.

I'm going to just give a brief overview of how I would do this and we can pick up on any details you want help with...

Main computer:

I would add a PCI express hard drive controller card. This card could have features for RAID or not but I would suggest a card with at least one mini-SAS (SFF-8087, SFF-8088) connection. A mini-SAS supports at least 4 hard drive devices per cable and depending on the PCIe card you may have an External mini-SAS (SFF-8088).

RPC-4020:

I would use a SAS Expander, you can think of the expander as acting like a network switch for hard drives. There are a few expanders to choose from, the main difference are the number of mini-SAS connections included. Some have SFF-8088 connections so you will not have to buy an SFF-8087 to SFF-8088 adapter, like the HP Expander, although you will need to pay attention to powering the expander. The HP Expander doesn't include a Molex power connection and needs a PCIe connection or special hardware to power it.

Five SFF-8087 connections from the expander will go to the RPC-4020's backplane to connect all the hard drives.

I've mentioned a bit about SAS (Serial Attached SCSI) which uses a point-to-point protocol replacing SCSI and is often compared to SATA, but keep in mind, SATA drives can work over SAS connections.

This would be the basics for how to physically connect it all together, from here I would start thinking about what kind of features I wanted like RAID support, and what kind of drives I would be using. You mentioned that you want to use 3TB drives, I would look into which controller chipsets support >2TB drives, what kind of interconnects would I need (SATA 3 Gbit/s or SATA 6 Gbit/s)? etc...

Edit: The RPC-4020's backplane actually takes SATA connections, in that case you would need mini-SAS to SATA breakout cables. The RPC-4220's backplane will take the mini-SAS connectors.
 
Last edited:
Bobby -
Thanks - that gives some insight into what I need.
>> think of the expander as acting like a network switch for hard drives <<
That is REALLY helpful..... it is my failing, but I just never thought of it like that!
FWIW, the 10 x SATA3 drives are my main concern - trying to get SATA3 through all the components.
 
Tom- With the exception of the new 1TB platter Seagate 3TB drives, none of the existing 3TB drives will even saturate a SATA-1 bus, let alone SATA-2 bus,or SATA-3 bus. That being the case, other than giving you speedier options in the future, don't let that be the determining ideal.
 
For 3TB drives you need current hardware anyway, and that will be SAS/SATA 6Gb/s. However, mixing SATA2 and SATA3 drives on the same hardware might make all of it go down to SATA2. But that's not really a problem for hard drives.
 
mwroobel said:
Tom- With the exception of the new 1TB platter Seagate 3TB drives, none of the existing 3TB drives will even saturate a SATA-1 bus, let alone SATA-2 bus,or SATA-3 bus. That being the case, other than giving you speedier options in the future, don't let that be the determining ideal.
Click to expand...

I'm just thinking of what happens if I implement RAID in the future that might saturate SATA2.
Thanks
 
Aesma said:
For 3TB drives you need current hardware anyway, and that will be SAS/SATA 6Gb/s. However, mixing SATA2 and SATA3 drives on the same hardware might make all of it go down to SATA2. But that's not really a problem for hard drives.
Click to expand...

I could keep the SATA2 drives on my existing LSI 1068 or IBM IBM M1015 (rebranded LSI 9240-8i) by installing them in the computer case.
Thanks
 
tombew said:
I'm just thinking of what happens if I implement RAID in the future that might saturate SATA2.
Thanks
Click to expand...
It doesn't matter. Each drive still is unlikely to fully saturate the sata-1 bus. You could have an 8 spindle raid6 that may be capable of 600MB/s, but that is a bandwith requirement for the bus that the RAID controller is on, PCie for example, but you still need less than 150MB/s for each constituent SATA port.
 
You must log in or register to reply here.
Back
Top