WTB: Supermicro SC846

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Weapon

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Oct 19, 2013
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Looking for a barebones SC846 to use for a FreeNAS server. Needs to be compatible with X9 LGA2011 board, M1015 controller cards, and SATA drives. Also need the quiet PSUs as this is going in my house.

If there is an eBay seller anyone would recommended please post that too.
 

T_Minus

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Feb 15, 2015
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That means it's got a SAS1 backplane, and also why it's so cheap.

SAS2 backplane is gonna push it $100 more likely.
 

Blinky 42

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Aug 6, 2015
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I bought a 1U barebones X9 server from MrRackables (a.k.a. Unix Surplus) this week as well, positive overall experience with them.
They actually include the proper rails and shipped it in one of the boxes with the expand-to-fit foam stuff with the thin plastic sheeting so it survived the trip ok
 
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izx

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Jan 17, 2016
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Thanks for the tip that MrRackables == UnixSurplus,didnt know!
 

WeekendWarrior

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Apr 2, 2015
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Agreed that Mr. Rackables (a.k.a. unixsurplus.com) is good to deal with. Bought a couple 846s recently and they allowed local pickup (would have been around $60/box to ship apparently). Also charged $65 for the rails - seemed disinclined to bargain on rails. Also would not sell SAS2 backplane separately. But good to deal with notwithstanding these caveats.
 
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Weapon

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So what's the preferred backplane? SAS2? TQ? I read it's a pain to swap so I'll likely wait for one with the newer backplane.
 

T_Minus

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For the 846 I like the expander backplane but I use them for storage not IOPs/performance really.
 

izx

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Jan 17, 2016
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So what's the preferred backplane? SAS2? TQ? I read it's a pain to swap so I'll likely wait for one with the newer backplane.
For bulk storage and neat cabling, absolutely the SAS2 expander ones. They're not a pain to swap if the chassis is empty, just need a long Phillips magnetic screwdriver (they are also bolted into the bottom of the chassis).

The SAS1 expander backplanes can be buggy with SAS2/3 controllers and large capacity drives. Best to start off with a SAS2 BP.
 

pc-tecky

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May 1, 2013
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I've been watching these for a while. But the ones with SAS2 BP don't exist or carry a premium. Maybe 3 listings just for the SAS2 BP from $150-$250. Even complete solutions with same MoBo, CPUs, RAM, & LSI Raid: SAS[1] version is something like $600-$800 while SAS2 version is $1100.-$1300.
 

izx

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Jan 17, 2016
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SAS[1] version is something like $600-$800 while SAS2 version is $1100.-$1300.
If you don't mind an 847, @sfbayzfs has them with SAS2 BP + SQ power supply for MUCH cheaper:

Supermicro rackmount chassis with all drive trays/screws and SFF-8087 cables to all drive bays. Add $60 for quick rails for any of these.
  • $560 SC847 4U 36-bay chassis with 2x 1400W gold or 1x 1K28P-SQ platinum PSU, SAS2 expander backplanes
I've bought quite a few of the items (that used to be) on that post, he's a stand-up guy.
 

sfbayzfs

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May 6, 2015
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* Edit - adding more backplane swapping details since I just swapped a pair 10 minutes ago :) also clarifications, and other direct backplane use cases and PDB notes *

Thanks for the mention - all but one of my extra 847s are claimed at this point, PM me if you decide you're interested in the last one :) If you can deal with low profile cards and drives on both ends of the chassis, I really like them a lot - the rear of the chassis has an easy to slide out 2U motherboard tray above the rear 12 drives. And of course, they only come with PWS-1K28P-SQ compatible PDBs AFAIK.

If you don't need more than 16 drives, I would highly recommend the SC836 3u units - they are a lot like an SC846, but the SAS2 expander backplanes can be found for cheaper. Plus the control panel is on the main part of the chassis, less damageable than the power switch panel on the left handle of the SC846 and SC847. (I have a couple of extra SC836 with TQ backplanes and a couple with SAS2 EL1 backplanes, which I am going to put the 1280W SQ compatible PDB into)

Although I haven't bothered doing a lot of testing both ways, to sum up my research, which includes others' findings I have seen reported here and in other forums:
  • Megaraid cards seem to have to have just the right firmware revision to work with the SAS1 backplanes, but IT mode HBAs are much more happy with them.
  • The drives larger than 2TB causing problems in fully populated SAS1 backplanes thing seems to only apply to the 24-bay backplanes, not 16-bay and 12-bay ones.
  • The detection problems may only apply to certain drive models, but I have not been able to get enough details from those who know.
I ended up replacing all of my SAS1 backplanes since even though ~160+ per SAS2 backplane is considered a good deal, I think it is worth it for the known reliability and ease of use of SAS2 backplanes over SAS1, even though SAS1 is perfectly serviceable for most situations - SAS1's 12 GBPS to 24 drives is somewhat limiting, but you can still get close to saturating 10G, and 48GBPS from double cabled SAS2 is more than enough bandwidth for spinners. I can confirm all Supermicro 24-bay 4U backplanes are mounted with just 5 screws at the bottom of the case and 4 on the top, plus 2 of the recessed ones on the outside of the case, on the right, and a magnetic screwdriver definitely helps. The front backplane is a little tight against the front fan midplane, be patient and careful and you'll be fine. The rear backplane is super easy to access in contrast since it is under the motherboard tray with plenty of room - 4 screws on top and optional 3 screws on the bottom, which are only used if your backplane has the metal frame (the ones I was taking out did not.) There are notches to fit the bottom of the backplane board into in the bottom of the chassis, which are also compatible with a framed backplane, go supermicro for interchangeability!

I also think the SAS2 expander backplanes are worth it over direct backplanes - they include the 36-port version of the chip in the 24-port Intel/LSI SAS expander, and even the more common $200-250 per backplane is still cheaper than buying 2 Intel expanders and cables to hook them up to a TQ or A backplane, plus the airflow is better airflow, etc.

The one case when I would use a direct backplane is if you are going to use SSDs with adapters in some of the bays, or want to split the backplane to 2 different controllers, a good trick for this in a 24-bay case with just 1 Intel expander is to single cable the expander to the controller for 20 of the drives, and then directly attach the other 4 ports on the controller (assuming an -8i card) to the other 4 bays for SSDs or some other sort of bandwidth-critical drives.

Another direct backplane use case would be to use 2 different controllers with different bays - for a 4U, dual-uplink an Intel expander between an -8i controller and 16 bays, and connect the other 8 bays directly to another controller. In this case, the -TQ backplane gives you more flexibility in how you allocate the bays, I have heard that the -A backplanes connect the groups of 4 drives column by column, whereas I like to fill bays row by row, then I always have groups of 4 drives across per group no matter what size the case instead of split columns in a 4U case.
 
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pc-tecky

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@sfbayzfs, I'm interested, but I'll have to hold off. Mentioned elsewhere, noise is huge factor.

I have 2x 2U Chenbro RM21400 w/ 6-hotswap and 5.25", aside from the noise, I don't have a MoBo or an HBA card to use them effectively as desired. In another post (from Patrick), it was recommended to use 4U to reduce noise. I suppose 3U would work as well. (I have more to add later. Update: 10 hours later, I have no idea what I wanted to add. Blah!)
 
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sfbayzfs

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I am also going to try a different wide PDB units in an SC836 in the next few days - checking my SC847 chassis' some have PDB-PT847-8824 and some have PDB-PT416-8824 - the look almost identical, but the second 8-pin CPU power connector is shorter on the PT416 version (most Supermicro motherboards need the second 8pin CPU power at the back of the motherboard anyway, but worth considering for other boards)
 

Terry Kennedy

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Jun 25, 2015
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I have heard that the -A backplanes connect the groups of 4 drives column by column, whereas I like to fill bays row by row, then I always have groups of 4 drives across per group no matter what size the case instead of split columns in a 4U case.
That is correct. It also spreads the connectors out across the backplane instead of in a neat row, so unless you get a bunch of custom-length cables, you end up with odd lengths of cable stuffed in the chassis. I use 3M High Routability cables in the systems I build:

This is a completely flat cable which can be folded into complex origami patterns without affecting signal integrity.