Last month’s blog post about building our Backblaze storage pods generated a ton of interest and many people are building their own pods! Our post also generated a ton of questions so below we answer the common ones and provides more detail about where to get components.
Detailed Backblaze Storage Pod Parts and Vendor List
Seagate ST31500341AS 1.5TB Barracuda 7200.11 SATA 3Gb/s 3.5″
– or the slower low power (LP) version –
Backblaze now uses the low power drives.
Custom Designed 4U Red Backblaze Storage Pod Enclosure
Protocase is excellent at making custom cases in small quantities and in response to demand have dropped the price of the Backblaze storage pod enclosure to $700 each if you order 20 or more. Other case manufacturers can also build these cases from the 3-D model.
Zippy PSM-5760 760 Watt Power Supply with Custom Wiring (qtys of 200+)
Zippy Technology Corp. provides the power supplies.
List price is about $500/unit.
For quantities of 100+ (50 pairs), contact Mason Lee
U.S. West Pacific branch of Zippy: +1-949-366-9525
For smaller quantities, the Enermax Modu82+ 525W PSUs works well in the Backblaze storage pod and since those power supplies are modular it is easier to design the custom wiring harness. For $25 Enermax used to make the custom wiring harness but we have heard reports that they will no longer do this. If this is the case, since the power supply is modular, you could make your own custom wiring harness. The only catch is that you need a motherboard stub to turn the second PSU on/off. This is a $1 part but can be hard to find.
Chyang Fun Industry (CFI Group) CFI-B53PM 5 Port Backplane (SiI3726)
CFI has now setup a complete, and very reasonable, pricing table for people who wish to purchase these port multiplier backplanes directly. Their pricing is:
To purchase, visit: www.chyangfun.com
Or contact James at: (886-3)363-1521 Ext.215
Note: If you are using latching SATA cables, make sure to ask for the port multipliers that support a latch-housing on the SATA connector.
Intel E8600 Wolfdale 3.33 GHz LGA 775 65W Dual-Core Processor
Syba SD-SA2PEX-2IR PCI Express SATA II Controller Card (SiI3132)
Addonics ADSA4R5 4-Port SATA II PCI Controller (SiI3124)
Intel BOXDG43NB LGA 775 G43 ATX Motherboard
Mechatronics G1238M12B1-FSR 120 x 38 mm 2,800 RPM 12V Fan
Or contact John Burke at: 800-971-4242
Kingston KVR800D2N6K2/4G 2x2GB 240-Pin SDRAM DDR2 800 (PC2 6400)
Western Digital Caviar WD800BB 80GB 7200 RPM IDE Ultra ATA100 3.5″
Western Digital drive listed has recently been discontinued. This is the closest match:
Western Digital Caviar SE WD800AAJB 80GB 7200 RPM 8MB Cache IDE Ultra ATA100 3.5″ Internal Hard Drive – OEM
However, most drives will work for the boot drive. We prefer PATA drives since this keeps the device name separate from the SATA data drives.
FrozenCPU ele-302 Bulgin Vandal Momentary LED Power Switch 12″ 2-pin
Make sure you pick the “2pin” cable option.
SATA II Cable, 90 Degrees/straight with Locking Connectors
Fastener SuperStore 1/4″ Round Nylon Standoffs Female/Female 4-40 x 3/4″
Aero Rubber Co. 3.0 x .500 inch EPDM (0.03″ Wall)
Ask for Steve Ricker
Vantec VDK-PSU Power Supply Vibration Dampener
This Ventec part has been out of stock for a while so you can also use:
Fansis Anti Vibration Soft Silicone Power Supply Gaskets.
Acousti Ultra Soft Anti-Vibration Fan Mount AFM02
http://www.quietpcusa.com/ page for this part.
Note that this link is to an 8-pack and you actually need 12 pieces.
Acousti Ultra Soft Anti-Vibration Fan Mount AFM03
Small Parts MPN-0440-06P-C Nylon Pan Head Phillips Screw 4-40 x 3/8″
House of Foam 16″ x 17″ x 1/8″ Foam Rubber Pad
Tips and Tricks for Building a Backblaze Storage Pod
Many people said, “Oh, I’ll build one of these pods but switch the drives for 2 TB drives or ones from XYZ vendor.” We tried drives from Western Digital, Hitachi, Samsung, and Seagate; 1 TB, 1.5 TB, and 2 TB drives; and consumer and enterprise drives. Some of these drives performed terribly – dropping out of the RAID array on a regular basis. Other performed ok. The Seagate Barracuda 1.5 TB low power drives have worked best for us. The 2 TB Seagate drives have also worked well but currently cost more per GB than the 1.5 TB drives; the Samsung low power drives have extremely high error rates; Hitachi and Samsung 7200 RPM drives performed well but we have done limited testing; and the Western Digital drives have not performed well in our setup. (Note: this is not necessarily to say these drives are good or bad, just how well they performed in this configuration.)
Tons of commenters worried about Backblaze storage pods BBQ’ing the drives. On the contrary, heat has not been an issue at all, six fans are definitely overkill and there are opportunities to reduce the number of fans. However, if you change the case design, type of drives, etc. – make sure you monitor what impact your changes have made.
We settled on our power supplies by figuring out the least expensive way to get high-efficiency power. If switching power supplies, ensure you have smooth power and there is plenty to spin up the drives from a cold start without being too close to the margin. In general, you need significant power on 5 volts (about 40 – 50 amps) which is what makes finding alternate power supplies a challenge.
We worked hard to reduce vibration in the storage pods. Nylon screws, rubber fasteners for the fans, HD anti-vibration sleeves, foam insulation, etc. were all to dampen vibration. There is some data to show that our focus on vibration was important… though in discussions with the drive manufacturers, they claim that vibration is more likely to impact performance, not reliability. Having said that, if you change parts, make sure you are not increasing vibration.
While it’s tempting to lace up the cables tightly, they should actually be fairly loose so they do not pull on the connectors. And, even more important, ensure you are getting cables with good connectors. The actual cables rarely break, but connectors make a big difference: gold plated, well curved springy connectors that are shiny and not pitted if viewed under a microscope are ideal. (The ones we specified above are fine.) Also, ensure you get right angle SATA cable connectors, not left angle ones, so the cables route cleanly under the backplanes.
HD Anti-Vibration Sleeves
Vibration sleeves should be put on the drives at the level of the top grid such that they completely insulate it; the drives should not touch the grid. It takes a bit of practice at first, but quickly becomes easier than the standard process of putting four screws into a drive caddy.
Cold Swap Drives
Technically the system will support hot-swapping drives. However, we never do this. Hot-swapping drives on any system increases the likelihood of something going wrong. Since these pods are top-loaded and require moving the server to replace drives, it’s one more reason to power down before swapping drives. Here is a picture of me doing this:
Powering Up the Pod
We mentioned this in the original blog post, but it is worth repeating here: We recommend powering up PSU1 first, waiting until the drives are spun-up (and the power draw decreases to a reasonable level), and then powering up PSU2.
Test the Storage Pod
There are a number of tests that should minimally be run before deploying a storage pod into production. First, completely sync all the drives into a RAID array. This forces every sector on every drive to be read and some sectors to be written – a process that will take about 3 days for a pod full of 1.5 TB drives. Second, run a memory test on the system. And finally, run a load test on the storage pod. There are various tools out there to help with this process. (At Backblaze we wrote our own to best simulate a real production environment.)
Hopefully this helps those of you who are working on building your own version of the Backblaze Storage Pod. We still intend to provide blog posts covering vibration, drives, and other areas of the pod in detail. You should feel free to experiment; try different motherboards, CPUs, cases, fans, etc. Customize the Backblaze storage pod for your particular purpose. Do keep in mind that while it may seem that every component should work seamlessly with every other, it is not the case. If you are switching out pieces, expect to need to experiment to get the system working right.