Newbie questions on external drive cases

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wcage03

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All, thanks in advance for your help.

I have used FreeNAS for many years. My builds have always been hardware that is laying around rather than purchased on purpose for the task at hand. I am sure I have a non-efficient solution, but it hits the spot that I need and it makes me feel good to get some more cycles out of that old hardware.

I now find myself needing to expand my storage. In years past, I tended to move to larger disks and keep the numbers of disks down to where I could fit them into the case that was going to by my NAS. Very easy. I am now at a point where I would like to take advantage of an external case for the drives. I want to step up the game here and get to hot swappable disks and the ability to add to the array with less hassle.

Here is where I am hitting the limits of my knowledge. I know that I could go the route of a bigger case and put the mother board in there with enough sata ports to drive all of the disks, but I would prefer to go to an external case dedicated to the drives. The question is what is the correct way to connect that case? I have searched high and low and where I keep getting is either the solution where the NAS is a self contained box (like I have now) or the external enclosures are either full blown NAS already or they are metal DIY enclosures. I get the DIY approach to build the self contained, but not what is required for the stand-alone drive enclosure.

I know it is not an elegant solution to route a bunch of sata cables out of the back of the computer over to the external enclosure; what is the elegant way? eSata connectivity keeps popping up, so I am thinking that might be it, but if it is, how does that apply? It seems that this would allow for a single cable to go from the computer to the enclosure, but what happens on the enclosure side? Is there a board that would take this single cable input and burst it into the right number of sata connections for the drives housed there? I did read the term "port replicator" a few times without explanation. Is that the device?

I am familiar with the concept of a back plane for blade servers, does an external drive enclosure have to have that? What is required to be able to get a drive (and enclosure) to be hot swappable? I tend to refrain from popping the cover off my current NAS and yanking a drive out with it spun up so I would imagine that there is more to getting this feature than having a quick disconnect drawer. Am I right?

Anyway, I apologize for the length of this email and for (what I am sure to be) the basic nature of the questions, but I have been searching high and low for answers. If you can share some insight and/or point me in a more effective direction for my searches I would be most appreciative.
 

Chris Moore

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You have asked a big question and one of the reason that people tend to keep all the drives internal is because of the complexity of the answer. You are about to go down the rabbit hole.
Unfortunately the support for eSATA has not kept up with the times and although I use it for an external enclosure on my FreeNAS system, it is not without problems that would make it difficult (at best) and most people would call it unusable.
For easy, reliable operation, you should use SAS (Serial Attached SCSI). Here is a link to some info about it:
https://simple.wikipedia.org/wiki/Serial_Attached_SCSI
another link:
https://forums.freenas.org/index.ph...imer-on-basic-sas-and-sata.26145/#post-165190
Then there is SAS Expanders:
https://forums.freenas.org/index.php?threads/sas-expanders.36394/#post-222086

This is a SAS controller that you can connect an external enclosure to:
https://www.ebay.com/itm/LSI-9207-8...A-External-ZFS-JBOD-IT-Mode-HBA-/162563989119
You would then use this kind of cable (or two of them) to connect that card to the external enclosure:
https://www.ebay.com/itm/CableCreat...088-Male-to-Mini-SAS-26-SFF-8088/332345292647
Then you could connect this type of external enclosure:
https://www.ebay.com/itm/8-bay-6G-S...pander-compare-to-Areca-ARC-4036/252561368016
Now, that enclosure does not have a SAS expander so you get 8 SAS lanes from the card to the enclosure and you can only connect 8 drives, but if you use a SAS Expander enclosure, you can get something like this:
https://www.ebay.com/itm/15-bay-6G-Trayless-SAS-Expander-External-Tower-Enclosure-JBOD/232322124265
If you want to go rackmount, they make those also:
https://www.ebay.com/itm/4U-Supermi...Storage-Expander-SC847E16-RJBOD1/142570604660

By the way, some people spend years learning about all the details of how this works. There really is quite a lot to it.
 

Chris Moore

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Anyway, I apologize for the length of this email and for (what I am sure to be) the basic nature of the questions, but I have been searching high and low for answers. If you can share some insight and/or point me in a more effective direction for my searches I would be most appreciative.
PS, once you spend the money on interface cards, cables and extra enclosures, most people find it more cost effective to just buy a used 24 bay rack server and use that instead, unless you plan to have more than 24 hard drives.
I have (for my work) many racks filled with enclosures and hundreds of disks online, but you probably don't need that at home or is this for a business?
What is it you plan to do with this?
 

wcage03

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Thanks for the direction... I have lots of reading to do. This is for my home so I am on the lower end of the scale of what you are describing (10 disks maybe). This is more of a hobby rather than a requirement. I don't know if you remember Jerry Pournell from the old Byte magazine (showing my age). He used to have a column called "Computing at Chaos Manor". Kindof a similar situation for me. I like to learn and build. I end up with way over engineered solutions, but I usually get a lot of enjoyment (and a little bit of education) along the way.

I will dig into the links and, I am sure, come back out of the rabbit hole with more questions.
 

Arwen

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There is a gotcha with SAS and eSATA. If you use a SAS card but it's not connected to SAS disks or SAS expander, just SATA disks, then your configuration has the SATA cable limit. (SAS host ports can do SATA when connected to a SATA disk.)

It's one of those esoteric things that can bite you. Some one recommends a nice meter long 4 lane SAS cable but you use it for SATA disks without a SAS expander. With the internal cabling in the enclosure, (and any hot-swap carrier), that configuration may have exceeded SATA cable length specifications. Thus, reduced reliability. Never good for a NAS.
 

Jailer

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If you are looking at 10 drives and a small ish case the Lian Li PC-Q26 would be a good option for you and you wouldnt have to mess with an external enclosure and the complexities that come with it.
 

Chris Moore

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Thanks for the direction... I have lots of reading to do. This is for my home so I am on the lower end of the scale of what you are describing (10 disks maybe). This is more of a hobby rather than a requirement. I don't know if you remember Jerry Pournell from the old Byte magazine (showing my age). He used to have a column called "Computing at Chaos Manor". Kindof a similar situation for me. I like to learn and build. I end up with way over engineered solutions, but I usually get a lot of enjoyment (and a little bit of education) along the way.

I will dig into the links and, I am sure, come back out of the rabbit hole with more questions.
Here is another thread that came up related to this and I thought you would like to look at it:
https://forums.freenas.org/index.php?threads/enclosure-question.54787
 
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