SAS- A solution to all of my storage problems?

timmatimma

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Jul 16, 2010
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Hello everyone,

This one has me stumped. I can usually google for an hour or two and have a viable mechanism for how things work, but this doesn't seem to have a direct answer.

How exactly do you interconnect SAS blocks (RAIDS or JBODS) between motherboards? I can see that you can use a single HDD for a single port, and that you can install Controller cards, but I don't exactly see how you interconnect, say, two/three units in a rack together.

This functionality would allow me to upgrade the server system that I am running so that it would be much closer to a local filesystem. Currently using NFS + LDAP to accomplish the same thing. By and large it has worked flawlessly, but over a single 1Gb LAN connection it's.... Well It's not as fast as I would like.

Any input or articles will be met with enthusiasm and (lots of) appreciation.

-t33ma
 

DustinM

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Jul 13, 2010
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A lot of people connect SCSI RAIDS together with Fiber, others use serial cables.
Most of the time they are connected with network cable, then through a switch into a central computer. or you can Cluster them all before you setup a raid.

I'm sure there are many more ways.

And if you want faster speeds, you can always installed 2 or more NICs and Enable Line Aggregation.
Of course that last part was a joke... That's too expensive...
 

timmatimma

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Jul 16, 2010
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I had read that there was an '8 meter cable' that would be the equivalent of the "Network Patch" except it wouldn't require a NIC as it would connect to a SAS port or something like that.

http://features.techworld.com/storage/1319/sas-clusters--the-san-without-an-an/

I was hoping that what is described here is possible, and what components I would need to purchase per-unit on my server(s).
 

DustinM

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You mean something like this?

http://www.newegg.com/Product/Product.aspx?Item=N82E16812120082&cm_re=SCSI-_-12-120-082-_-Product

Except longer?


Maybe what you're looking for is in this.
http://www.newegg.com/Product/ProductList.aspx?Submit=ENE&DEPA=0&Order=BESTMATCH&Description=SCSI+Cable&x=10&y=30
 

MRFS

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Not sure I understand your question completely,
nevertheless FWIW:

You can insert an Infiniband multi-lane SAS/SATA cable
into many RAID controllers with ports at the rear panel
e.g.:

http://www.newegg.com/Product/Product.aspx?Item=N82E16816115062&Tpk=N82E16816115062
http://www.newegg.com/Product/Product.aspx?Item=N82E16816115082&Tpk=N82E16816115082


How you terminate the other end of those cables is really
a design decision that turns on the type of storage
enclosure you choose for your drives: some use a backplane
and others use a direct connection to the drive ports.


The Highpoint website has a neat "Cable Matrix" for mixing and matching:

http://www.highpoint-tech.com/PDF/RocketRAID_Cable_Matrix.pdf


There is one major feature about SAS connectors that you
may want to examine closely: the signal connectors are
"double-ported": this means that 2 different controllers
can connect to any given SAS drive at the same time,
for purposes of fail-safe redundancy.

Also, there is a "key way" which allows a SATA HDD
to connect to a SAS-compatible controller, but
a SAS HDD cannot connect to a SATA controller.


I assembled a few (poor) graphics of SAS connectors here:

http://www.supremelaw.org/systems/sas/



MRFS
 

timmatimma

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Jul 16, 2010
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O_O

Alright, so what I want to know is there a way to expand that "Double port" to an " x " port, x being some variable number of controllers.

I want to use a cluster of SAS/ SATA Disks. So ideally I would have a SAS RAID card /expander controlling a group of disks, and then that group of disks would shared through that x port to a cluster thats mounted in the same vicinity. (Like a SAN but concentrated to one "Controller" machine that has the same bandwidth as the "Node" machines, in my mind.)

Same kind of idea. I want to have failover across 8 or 10 machines that will be distributing a service via round robin or something (HA Cluster with failover)