README (5537B)
1 jbod 2 ============================================================================== 3 Design files for building a 4U, 19-inch, 800mm deep rackmount JBOD chassis. 4 5 jbod: Project Layout 6 ============================================================================== 7 Files for the sheet-metal enclosure can be found under the `openscad/` 8 subdirectory. These include all the code to turn the openscad script into 9 files ready to send for cutting and bending, and which hopefully result in a 10 suitable, rack-mountable chassis. 11 12 Files for all the PCBs can be found under the `kicad/` subdirectory. These 13 include a custom symbol library (e.g. for connectors missing from the standard 14 kicad library), the "mainboard" (such as it is), and the drive backplanes. 15 These should be ready to be converted to the relevant file formats to be 16 sent to be manufactured. 17 18 Code, scripts, and other extra resources can be found under the `extra/` 19 subdirectory. Code includes some build instructions, scripts should run 20 standalone where possible. 21 22 jbod: Design Notes 23 ============================================================================== 24 Some notes, in no particular order: 25 26 - The chassis is designed for "standard" 19-inch wide, 1000mm deep server racks 27 + The maximum width of a chassis in such a rack is 480mm 28 + The maximum depth of a chassis in such a rack is 900mm 29 + Heavy duty (<=200kg) slide rails will be around 0.75-inches wide per rail 30 + The maximum width of a chassis with rails is thus 17.5 inches 31 + The max. reasonable width for a chassis in such a rack is 17.5", or 440mm 32 + The max. reasonable height for a chassis in such a rack is 4U, or 177mm 33 34 - The chassis has the following dimensions: 35 + Front panel dimensions (w/h/d 482/177/2.5 mm) 36 + Enclosure dimensions (w/h/l 440/177/800 mm) 37 + The chassis supports heavy duty (<=200kg) rack rails 38 - https://www.jonathanengr.com/product/432-433-series/ 39 40 - The chassis front panel will be a stamped mesh, with rack handles 41 + The front panel grille will be a stamped mesh 42 + The front panel will have two substantial rack handles 43 + The front panel will have LEDs shoing the status of each drive 44 + The front panel will have debug IO for the motherboard via USB-C 45 46 - The chassis will have a tool-less top panel 47 48 - The chassis rear panel will contain solely PSU access, serial access, and IO 49 + The rear panel has meshes for exhaust airflow 50 + The rear panel allows access to the redundant 1+1 M-CRPS PSUs 51 + The rear panel allows serial access over both DB9 and RJ45 (exclusive?) 52 53 - The chassis has a two-chambered design for separate airflow regions 54 + One chamber is solely for the 3.5-inch disks, with 6x push-pull fans 55 + One chamber is for the PSUs, expanders, and motherboard, with 1x pull fan 56 + Noctua 140mm industrial 2000rpm pwm fans (w/h/l 140/140/25 mm) 57 - https://www.noctua.at/en/products/nf-a14-industrialppc-2000-pwm/specifications 58 + Noctua 120mm industrial 2000rpm pwm fans (w/h/l 120/120/25 mm) 59 - https://www.noctua.at/en/products/nf-f12-industrialppc-2000-pwm/specifications 60 + Noctua 80mm chromax swap pwm fans (w/h/l 80/80/25 mm) 61 - https://www.noctua.at/en/products/nf-a8-pwm-chromax-black-swap#hero 62 63 - The chassis supports redundant 1+1 CRPS 1000W+ PSUs 64 + Open Compute M-CRPS form factor standard PSUs (w/h/l 75/40/185+11 mm) 65 - https://www.opencompute.org/documents/m-crps-r1-v1p0-rc4-pdf 66 67 - The chassis holds 72x 3.5-inch disks in a 6x12 configuration 68 + 3.5-inch disk dimensions (w/h/d 101.6/26.11/146.05 mm) 69 + 3.5-inch disk w/ caddy dimensions (w/h/d 105/30/150 mm) 70 71 - The chassis supports up to 4x SAS expanders, with multipath to all disks 72 + 72 Disks mean we need 2 SAS expanders per disk, and 2x2 for multipath 73 + The chassis has 2 2x4 mini-sas HD (sff-8674) external ports per 2 expanders 74 - One 2x4 (x8) wide-port serves as the uplink to the HBA 75 - One 2x4 (x8) wide-port serves as the downlink to chained JBODs 76 - https://members.snia.org/document/dl/25967 77 + If splitting a single x4 port into 2x2 half-ports is allowed, we can use 78 40-port SAS expanders 79 + Otherwise, we must use 48-port SAS expanders 80 + Microchip SAS3x48 Expander 81 - https://www.microchip.com/en-us/product/PM8055 82 + Microchip SAS4x42 Expander 83 - https://www.microchip.com/en-us/product/PM8111 84 + Broadcom SAS35x40 Expander 85 - https://www.broadcom.com/products/storage/sas-expanders/sas-35x40 86 + Broadcom SAS4x40 Expander 87 - https://www.broadcom.com/products/storage/sas-expanders/sas-4x40 88 + Broadcom SAS35x48 Expander 89 - https://www.broadcom.com/products/storage/sas-expanders/sas-35x48 90 + Broadcom SAS4x48 Expander 91 - https://www.broadcom.com/products/storage/sas-expanders/sas-4x48 92 + Alternatively, a SAS4 backplane expander 93 - https://ipc.in-win.com/system/storage/upload/1741851115nFNAmXWopKzd9UPN.pdf 94 95 - Drives are in groups of 4, with 4 U.3 connectors per backplane 96 + Backplanes have a single sff-8654 8i U10 connector per backplane 97 - Each drive is connected in a x1 configuration to each expander 98 - Each drive can be connected to up to 2 expanders 99 100 - The motherboard supports SMBus, PMBus, UBM, PWM, and a serial console 101 + SMBus controls individual disks 102 + PMBus controls the PSUs 103 + UBM controls the motherboard and disk routing from the host 104 + PWM controls tehe fans 105 106 jbod: References 107 ============================================================================== 108 - https://www.aicipc.com/products-detail/j4078-01-35x/ 109 - https://www.aicipc.com/products-detail/j4108-01-35x/