TL;DR - Upgraded version of NR40700 with SAS3 (12Gbps) backplanes. Heavy and loud.
I recently picked up an IBM Slicestor 3448 (Chenbro RM43348) on eBay. They're currently listed at $595 but the seller accepted my Best Offer which was considerably less. It's definitely more expensive than a Chenbro NR40700 but the bandwidth upgrade is worth the delta, imo.
Included:
Chenbro - Products
They even have a marketing video on Youtube complete with dramatic music:
Backplanes
My main interest in this unit, as opposed to the Chenbro NR40700 , is in the backplane expanders. I'm new to SAS expanders so their capabilities may be entirely conventional but I was impressed none the less. They are 36 port SAS3 12Gbps and all 36 ports can be wide (dual link) and either initiator (HBA) or target (drive). They are wired up for 24 drives each with 3 mini-SAS HD ports for 12 initiator ports. This allows for 13.2GB/s (1,100MB/s x 12) per backplane or 26.4GB/s for the chassis!
Another attribute of interest is that the expanders buffer slower devices (3Gbps and 6Gbps) and transfer to the initiator at full 12Gbps. I confirmed that under linux my 6Gbps SATA drives reported a negotiated link speed of 12Gbps. This means that the initiator links can run at full speed at all times instead of dropping down to match the target's speed.
The expanders do not support SATA-1 or SAS-1 devices (1.5Gbps). The datasheet for the expander does not list 1.5Gbps capability and my old SATA-1 drives are not detected at all.
The drive connectors appear to be wired for wide links so fast SSDs should run at full speed.
The backplanes include (1) red LED per drive adjacent to the drive connector and the LED is controlled via SGPIO. I was able to control the LEDs using the linux ledctl utility. The front panel has 24 dual LEDs (red/green) per backplane. The green LED indicates activity and the red LED mirrors the backplane LED.
The backplanes are mounted on a tray which is (relatively) easy to remove.
Drive Trays
No drive rails/trays/caddies are included and, as far as I can tell, are simply not available anywhere. I ended up designing and 3D printing rails. There are 3D models for the NR40700 but I'm not sure they would have worked since they appear symmetrical. This chassis's drive slots are asymmetrical with the width being 18mm for the side closest to the connector and 15mm for the other side. Plus, with the LED on the backplane I wanted a light pipe. The light pipe is just a 2mm acrylic rod.
This first pass at rails isn't ideal but works in a pinch. There really isn't clearance for screws so I'm stuck with pins but the printed pins aren't exactly strong. I might go to stainless pins at some point.
Motherboard
The included motherboard is dual LGA2011 with 16 DIMM sockets and 3 x16 slots (not sure if they're also wired x16). I didn't have any CPUs to install so I could only verify that the IPMI was operational. The board MAC addresses indicate the origin as https://www.cas-well.com/. I've never heard of them but my guess is that they made a custom board for IBM. The BIOS is dated 2016 and it's unlikely any updates will be available.
Cables
Power Supplies
There are (2) 1,100W 1U power supplies that are 80+ Gold rated. According to the Chenbro documentation the 1,100 W rating is when supplied with 220VAC and it's only 800W when supplied with 110VAC. These guys are LOUD, as you would expect. They power up at full tilt (or nearly) then slowly ramp down to a near tolerable level. Interestingly, the fans do run when the system is powered down, but at a low speed.
The power supplies connect to a module via edge connectors which in turn connects to the two backplanes via edge connectors. The module provides breakout cabling. It is very well documented by Chenbro.
Fans
There are (4) dual axis, counter rotating, 80mm fan modules. Apparently, I didn't fully seat one of them because when I powered up the system the fans came on at 100% wide-open-throttle. Holly smokes they were LOUD and moved more air than I thought possible. If this thing was just a few pounds lighter I suspect it would be capable of powered flight. I have zero concerns about keeping 48 drives cool. Fortunately, once I ensured that all 4 modules were properly seated, the fan speed was much more tolerable. Even at the lowest fan speeds, you won't want to be in the same room for prolonged periods. The rest of the gear in my rack is loud so I really don't notice but I definitely did when I was running it in my office.
Racking
The chassis top panel is split front to back, allowing the top front to be opened without the chassis fully outside of the cabinet. The chassis is DEEP but this isn't all bad since I can push the two chassis above this one a bit forward to access the back half of the top panel to access the motherboard. I find that very convenient.
(don't hate on my cable mismanagement... I'm working on it!)
Miscellaneous
Also included are (2) LSI 3008 8 SAS3 12Gbps port cards. The firmware was old but was IT. It was trivial to update to the latest firmware. The inclusion of these cards almost pays for the price delta.
I bought a set of rails for a Chenbro NR40700 and they fit just fine. They were easy to source when I bought them but appear to be out of stock everywhere now so they may be hard to acquire.
The chassis has a removable motherboard tray with a complete set of standoff positions. I came up short by one standoff for my motherboard. It takes a rather peculiar standoff but it's the standard Chenbro standoff so, again, easy to source. The tray will accept boards from Micro-ITX all the way up to E-ATX. The tray also includes (2) 2.5" hot-swap bays. The tray supports low-profile cards only.
Updated 2020-08-17: My 3D printer models for drive rails are available at the link below. Both STL and f3d files are included.
drive.google.com
The LED light pipe is a 2mm acrylic rod.
I recently picked up an IBM Slicestor 3448 (Chenbro RM43348) on eBay. They're currently listed at $595 but the seller accepted my Best Offer which was considerably less. It's definitely more expensive than a Chenbro NR40700 but the bandwidth upgrade is worth the delta, imo.
Included:
- 48 drive 4U chassis
- (2) 1100W 1U 80+ Gold power supplies
- (1) Dual LGA2011 motherboard (unknown, likely custom) with heatsinks and ducts
- (2) LSI SAS9300-8i SAS3 12Gbps HBAs
- (4) Mini-SAS HD cables
- (4) Dual axis (counter rotating) 80mm fan modules
- (2) 24 drive backplanes with SAS3x36 12Gbps SAS expanders
- No drive caddies (top load or rear 2.5")
- No CPUs
- No RAM
- No power cables
- No rails
Chenbro - Products
They even have a marketing video on Youtube complete with dramatic music:
Backplanes
My main interest in this unit, as opposed to the Chenbro NR40700 , is in the backplane expanders. I'm new to SAS expanders so their capabilities may be entirely conventional but I was impressed none the less. They are 36 port SAS3 12Gbps and all 36 ports can be wide (dual link) and either initiator (HBA) or target (drive). They are wired up for 24 drives each with 3 mini-SAS HD ports for 12 initiator ports. This allows for 13.2GB/s (1,100MB/s x 12) per backplane or 26.4GB/s for the chassis!
Another attribute of interest is that the expanders buffer slower devices (3Gbps and 6Gbps) and transfer to the initiator at full 12Gbps. I confirmed that under linux my 6Gbps SATA drives reported a negotiated link speed of 12Gbps. This means that the initiator links can run at full speed at all times instead of dropping down to match the target's speed.
The expanders do not support SATA-1 or SAS-1 devices (1.5Gbps). The datasheet for the expander does not list 1.5Gbps capability and my old SATA-1 drives are not detected at all.
The drive connectors appear to be wired for wide links so fast SSDs should run at full speed.
The backplanes include (1) red LED per drive adjacent to the drive connector and the LED is controlled via SGPIO. I was able to control the LEDs using the linux ledctl utility. The front panel has 24 dual LEDs (red/green) per backplane. The green LED indicates activity and the red LED mirrors the backplane LED.
The backplanes are mounted on a tray which is (relatively) easy to remove.
Drive Trays
No drive rails/trays/caddies are included and, as far as I can tell, are simply not available anywhere. I ended up designing and 3D printing rails. There are 3D models for the NR40700 but I'm not sure they would have worked since they appear symmetrical. This chassis's drive slots are asymmetrical with the width being 18mm for the side closest to the connector and 15mm for the other side. Plus, with the LED on the backplane I wanted a light pipe. The light pipe is just a 2mm acrylic rod.
This first pass at rails isn't ideal but works in a pinch. There really isn't clearance for screws so I'm stuck with pins but the printed pins aren't exactly strong. I might go to stainless pins at some point.
Motherboard
The included motherboard is dual LGA2011 with 16 DIMM sockets and 3 x16 slots (not sure if they're also wired x16). I didn't have any CPUs to install so I could only verify that the IPMI was operational. The board MAC addresses indicate the origin as https://www.cas-well.com/. I've never heard of them but my guess is that they made a custom board for IBM. The BIOS is dated 2016 and it's unlikely any updates will be available.
Cables
- (1) 24-pin ATX power
- (2) 8-pin 12V (CPU power)
- (1) cable with (2) SATA power
- (1) cable with (1) 4-pin Molex
- (1) USB 8-pin header cable for (2) front panel ports
- (4) 5-pin fan connectors with (2) tach wires (fits standard 4-pin header but only signals 1 fan in that case)
- (1) PM SMB
- (1) Front panel (Power LED, ID LED, System Fault LED, Power Button, Reset Button, ID Button, IPMI SMB)
Power Supplies
There are (2) 1,100W 1U power supplies that are 80+ Gold rated. According to the Chenbro documentation the 1,100 W rating is when supplied with 220VAC and it's only 800W when supplied with 110VAC. These guys are LOUD, as you would expect. They power up at full tilt (or nearly) then slowly ramp down to a near tolerable level. Interestingly, the fans do run when the system is powered down, but at a low speed.
The power supplies connect to a module via edge connectors which in turn connects to the two backplanes via edge connectors. The module provides breakout cabling. It is very well documented by Chenbro.
Fans
There are (4) dual axis, counter rotating, 80mm fan modules. Apparently, I didn't fully seat one of them because when I powered up the system the fans came on at 100% wide-open-throttle. Holly smokes they were LOUD and moved more air than I thought possible. If this thing was just a few pounds lighter I suspect it would be capable of powered flight. I have zero concerns about keeping 48 drives cool. Fortunately, once I ensured that all 4 modules were properly seated, the fan speed was much more tolerable. Even at the lowest fan speeds, you won't want to be in the same room for prolonged periods. The rest of the gear in my rack is loud so I really don't notice but I definitely did when I was running it in my office.
Racking
The chassis top panel is split front to back, allowing the top front to be opened without the chassis fully outside of the cabinet. The chassis is DEEP but this isn't all bad since I can push the two chassis above this one a bit forward to access the back half of the top panel to access the motherboard. I find that very convenient.
(don't hate on my cable mismanagement... I'm working on it!)
Miscellaneous
Also included are (2) LSI 3008 8 SAS3 12Gbps port cards. The firmware was old but was IT. It was trivial to update to the latest firmware. The inclusion of these cards almost pays for the price delta.
I bought a set of rails for a Chenbro NR40700 and they fit just fine. They were easy to source when I bought them but appear to be out of stock everywhere now so they may be hard to acquire.
The chassis has a removable motherboard tray with a complete set of standoff positions. I came up short by one standoff for my motherboard. It takes a rather peculiar standoff but it's the standard Chenbro standoff so, again, easy to source. The tray will accept boards from Micro-ITX all the way up to E-ATX. The tray also includes (2) 2.5" hot-swap bays. The tray supports low-profile cards only.
Updated 2020-08-17: My 3D printer models for drive rails are available at the link below. Both STL and f3d files are included.
chenbro drive rails.zip
drive.google.com
The LED light pipe is a 2mm acrylic rod.
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