Rackable Systems drive capacity limit?


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Gang,

 

Snooping around fleabay I have found some stupendous deals on old Rackable Systems servers.  In particular, the 12-bay dual Xeon systems are only 15.5" deep.  While I desperately want to move to a rack chassis, I am depth-limited in the chassis I can choose.  The Rackable Systems would fit perfectly (physically), but I've read elsewhere that, with older generation servers, there is a TB limit to the disks that can be used.  I'm wondering if this is a function of the chipset, or the SATA backplane perhaps?  I believe the backplane is simple an electrical concentrator (correct me if I'm wrong), but I've seen posts with systems using new-ish CPUs and chipsets which should support, for example, 8TB disks, where the poster states that he cannot get them to be recognized.

 

Before I explore purchasing one of these systems (chime in if you're using one), can anyone speak to disk capacity limitations of older-gen server hardware?

 

Thanks.

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The backplane is actually a physical board with connectors on it which has to be replaced, the ones that only support up to 2TB are SAS backplanes, what you want is a SAS2 backplane to go beyond the 2TB limit. I have seen some Supermicro servers with SAS backplanes and priced out SAS2 backplanes from $300-500 so while the server may be a deal, upgrading the backplane can cost. I was fortunate enough on eBay to score a Supermicro 36bay chassis complete with motherboard, dual (older) Xeons and 52GB of ECC RAM and a SAS2 backplane up here in Canada for a great price. I hear the servers with SAS2 backplanes are harder to find now.

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Thanks for the reply!  The system I am looking at had 16 individual SATA connectors on the backplane, and some models include a 3Ware SATA RAID controller.  So I don't think SAS is going to be an issue here.  Still wondering if I just misread the posts I mentioned earlier (maybe I mistook SAS for SATA at some point).... Wondering if any plain old SATA backplane can support and size drives -- I assume like I said its just an electrical connection passed through to the host controller.

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You can never be sure which is why you have to ask the seller, if they don't know then its a gamble. I'd hate to be stuck with a server that was limited to 2TB drives, so if you can, make absolutely sure before you buy. One piece of advice, before I bought my server I emailed Supermicro tech support because I wanted to know if one HBA could support all 36 drives and they were very helpful, sending me a diagram and answering all my questions.

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Thanks again.  I'll contact SGI to see if they can advise on a server so old, but they deal with supercomputers and mega-million-dollar server farms, so I'm not sure a peon like me and my $300 ebay purchase are gonna rate.  We'll see.  In the meantime I have contacted the seller, hopefully they know for sure.  I did find a spec sheet on the server that I am looking at, which advised the 12-bay version supports up to 100TB.  But I'm guessing there are various revisions of backplanes, based on the number of years the server was in production.

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13 hours ago, tucansam said:

Thanks for the reply!  The system I am looking at had 16 individual SATA connectors on the backplane, and some models include a 3Ware SATA RAID controller.  So I don't think SAS is going to be an issue here.  Still wondering if I just misread the posts I mentioned earlier (maybe I mistook SAS for SATA at some point).... Wondering if any plain old SATA backplane can support and size drives -- I assume like I said its just an electrical connection passed through to the host controller.

I have 2 Supermicro rack cases, a 24 bay CSE 846 and a 36 bay CSE 847. I only have simple pass trough backplanes, SAS846TQ which has 24 SATA connectors onboard which are connected with 6 breakout cables to 3 M1015 controllers and the other server has a SAS846A and SAS826A backplane which are connected through 6 and 4 SFF8087 to SAS8087 cables. All backplanes support 8 TB disks just fine upto 6BG/s. If in doubt you can always ask Supermicro. 

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