Storage Pod 4.5 – Tweaking a Proven Design

March 5th, 2015

Storage Pod 4.5

To get the latest updates and information
on ALL of the Storage Pod versions. Click Here.

It has been nearly a year since we published an update to our Storage Pod design. Over the last few months we have been deploying Storage Pod 4.5, which is known internally as Storage Pod Classic. The reason for the “classic” nickname comes from the fact that Storage Pod 4.5 is derived from our Storage Pod 3.0 chassis and design. Storage Pod 4.5 returns to the backplane-based design of Storage Pod 3.0 but incorporates upgrades that improve reliability and reduce cost. The result is that Storage Pod 4.5 delivers 180 TB of data storage for only $0.048 per Gigabyte, our lowest cost ever.

What’s New In Storage Pod 4.5

Storage Pod 4.5 is built on the same chassis as Storage Pod 3.0, but with an upgraded parts list. The upgraded items are:

  1. Backplanes
  2. SATA cards
  3. CPU

To the delight/dismay of many in the reddit community, we did not change the on-off switch.

1) Back to Backplanes

    One of the principle design decisions we made in Storage Pod 4.5 was to return to using 5-port SATA backplanes versus the direct-wire design of Pod 4.0. We’ll dig in to why we returned to backplanes a little later in this post, but for the moment let’s cover the backplanes we are using in Pod 4.5.

    At the core of the new backplanes is the Marvell 9715 chipset. Over the years, Marvell has proven to be committed to the storage market and manufacturing the chipset fits nicely into their business. Both Sunrich and CFI use the 9715 chipset as part of their 5-port backplanes. We now have a backplane that is readily available, well supported and faster with 6 Gbps SATA-3 throughput.

2) New SATA Cards

    For Storage Pod 4.5 we upgraded to SATA cards manufactured by Sunrich using the Marvell 9235 chipset. The same chipset is also used by SYBA in their latest SATA cards. When combined with the upgraded backplanes, the new SATA cards deliver 6 Gbps SATA-3 throughput.

3) Upgraded CPU

    The CPU was upgraded from an i3-2100 to an i3-2120. The i3-2100 has been EOL’d by Intel and the i3-2120 delivers slightly better performance for the same price. We’ve also tested the i3-3240 and it worked fine. Other LGA 1155 socket CPUs should work as well, although we have not tested any beyond those mentioned.

Storage Pod Costs

Storage Pod 4.5 is less expensive to build and fill with hard drives than all its predecessors. The entire system, fully populated with 180 Terabytes worth of hard drives, costs Backblaze less than a nickel per Gigabyte. With larger capacity hard drives now coming to market, the cost/GB for hard drive storage should continue to decrease and drive down the cost of each Storage Pod we build. This will allow us to continue to charge just $5/month for our unlimited online backup service.

Below are the Backblaze costs for building the different Storage Pod versions.

Storage Pod Cost History

Building your own Storage Pod or having a Storage Pod built for you will likely cost somewhat more, but the cost of the hard drives will continue to be the main cost component.

Our Round Trip to Backplanes – The Inside Story

Each month Backblaze needs to build and deploy 20 to 30 Storage Pods. To do this, we employ a contract manufacturer to bend the metal and assemble the parts into a Storage Pod that we load test and qualify before placing into service. Backblaze then monitors and maintains the active Storage Pods. Prior to Storage Pod 4.0, we had built and deployed nearly 800 backplane-based Storage Pods.

Two unrelated events drove our decision to go down the direct-wire design of Storage Pod 4.0. First, we had a dwindling supply of 5-Port backplanes as Silicon Image stopped making the chipset used to manufacturer the backplanes and second, our existing contract manufacturer was having trouble meeting our production schedule for Storage Pods.

Into the breach stepped Protocase. Over the years, they have been a huge Backblaze Storage Pod supporter and created their 45 Drives division to sell Backblaze inspired storage servers. Protocase started building version 3.0 Storage Pods for us and when we decided to go with the direct-wire design described in the Storage Pod 4.0 blog post we used Protocase as our primary contract manufacturer.

With Storage Pod 4.0 being a completely new design, we had expected there to be “growing pains.” Indeed, looking back at Storage Pod 1.0, it went through multiple versions before it was ready for an operational environment. For Storage Pod 4.0, Protocase diligently worked with us over the course of several months to address the growing pains and get Pod 4.0 systems deployed in our data center.

While we worked to get Storage Pod 4.0 ready, we still had to deploy 20-30 operational storage pods each month. After testing out several local contract manufacturers, we found Evolve Manufacturing. They were eager, smart, located nearby, and proved to be excellent at building Storage Pods. At the same time, new vendors stepped forward with 5-port backplanes and SATA cards based on the Marvell chipsets. This meant we had everything we needed to go back to the future and build backplane-based storage pods to meet our operational needs and that’s what we did.

Late last year we finally made the decision to stop investing in the direct-wire design of Storage Pod 4.0 and proceed with upgrading our backplane-based design and Storage Pod 4.5 was born. To date we have deployed nearly 100 Storage Pod 4.5 systems.

What Should You Buy?

If you are looking to purchase a storage server inspired by Backblaze, here a couple of vendors we recommend:

    Evolve Manufacturing – they are our supplier of Version 4.5 Storage Pods. Please check out They will sell you a fully assembled Storage Pod 4.5 chassis (without drives), a Storage Pod 4.5 Kit (unassembled, no drives), or just a Storage Pod 4.5 metal chassis.

    Protocase – they helped design Version 4.0 and prior Storage Pods. They also supplied Version 3.0 and Version 4.0 Storage Pods for Backblaze. Please check out to see the wide variety of products they offer inspired by Storage Pod 4.0 and prior designs.

    [9-1-2015 – Updated Storage Pod supplier information – Editor]

Making a Storage Pod

If you are inclined to make your own Storage Pod, we’ve included a list of the parts you’ll need Appendix A. Most of the parts can be purchased online via Amazon, Newegg, etc. Some parts, as noted on the parts list, can be purchased through either a distributor or from one of the contract manufacturers. Since Storage Pod 4.5 is similar to Storage Pod 3.0 you can still use this nice screen shot assembly walk-through from Protocase and it’s companion Storage Pod assembly overview (PDF, 1.5MB) for guidance.

As a reminder, Backblaze does not sell Storage Pods and the design is open source so we don’t provide support or warranty for people who choose to build their own Storage Pods. You can find fellow Pod builders at and

Appendix A: Storage Pod 4.5 Parts List

Below is the parts list for building Storage Pod 4.5. The price shown is the current list price of the items needed to build one storage pod. You may be able to find a lower price for some of these items.

4U Custom Case
Includes case, anti-vibration assemblies, power supply bracket, etc.
760 Watt Power Supply
Zippy PSM-5760V Power Supply
On/Off Switch
FrozenCPU ELE-272 Momentary LED Power Switch
Case Fan
Fan Connection Housing
Dampener Kits
Power Supply Vibration Dampener
Soft Fan Mount
AFM02B (1 flat end)
Soft Fan Mount
AFM03B (2 tab ends)
Supermicro MBD-X9SCL-F (MicroATX)
Intel Core i3 processor i3-2120
240P PC3-10600 CL9 18C 256X8 DD
Port Multiplier Backplanes
5 Port Backplane (Marvell 9715 Chipset)
4-PORT PCIe Express (Marvell 9235 chipset)
SATA cables RA-to-STR 3 ft locking from Nippon Labs
Boot Drive
80GB 7200RPM SATA 2.5 IN
Screw: 4-40 X 3/16 Phillips 100D FLAT SST
Screw: 6-32 X 3/16 Phillips PAN SST ROHS
Screw: 6-32 X 1/4 Phillips PAN ZPS
Screw: 4-40 X 5/16 Phillips PAN ZPS ROHS
Screw: 4-40 X 1/4 Phillips 100D Flat ZPS
Screw: 6-32 X 1/4 Phillips 100D Flat ZPS
Screw: M3 X 5MM Long Phillips, HD
Standoff: M3 X 5MM Long Hex, SS
Standoff: Round 6-32 X 1/4 Dia X 5/16 Lng
Crimp Terminal, 22-30 AWG Power (Tin)
Foam Tape, 1″ x 50′ x 1/16 in black


  1. Purchase from Evolve Manufacturing for price listed, plus tax, packaging, handing, and shipping.
  2. Sunrich and CFI make the recommended backplanes and Sunrich and Syba make the recommended SATA Cards. These items may be purchased via Arrow (a distributor) or Evolve Manufacturing.
  3. Nippon Labs makes the recommended SATA cables. They may be purchased from Evolve Manufacturing.
  4. The Boot Drive can be any 2.5 or 3.5 inch internal drive.


Andy Klein

Andy Klein

Andy has 20+ years experience in technology marketing. He has shared his expertise in computer security and data backup at the Federal Trade Commission, Rootstech, RSA and over 100 other events. His current passion is to get everyone to back up their data before it's too late.
Andy Klein

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  • disqus_8evUIphm4F

    I’d like to see the 4.5 Pod compared to SuperMicro’s ripoff the SC946ED-R2KJBOD:,1-2657.html

  • Jonny

    Does the Storage Pod 4.5 chassis support EATX motherboards?

  • Jonny

    If I buy a bare storage pod 4.5 chassis, do I have to use backpanes?

    Can I just directly wire my drives to the SATA cards on my MOBO? I want to build an unRAID server and a direct-wire approach seems so much cheaper and easier. It also seems like these backpanes are impossible to buy for normal consumers.

  • Andrew Baker

    Do you have any recommendations for a specific rack mounting solution for the 4.5 case? They are too wide for standard sliding rails, right?

  • Steve Williams

    Can I purchase these directly?

  • Santiago Draco

    Too bad you couldn’t take the time to list part numbers, links or any other info. You post these helpful articles then cut it short and make everyone hunt and hunt to find these things.

  • PeriscopeFilm

    Will these PCIe SATA III cards work with FreeNAS? Meaning are there FreeBSD drivers for these cards?

  • Alejandro

    The new 5 port sata backplanes are of the same dimensions and screw hole, sata connector position as the old ones used in the Pod <4 version?

  • Brandon Edwards

    Where can I get the backplanes? Seems everyone you mentioned does not list them and no one will reply to my inquiry.

  • Yuefeng Gao

    Hi. I noticed Supermicro released a 90-hard drive-solution recently (SC946ED-R2KJBOD ), can you compare the design of that one with storage pod? I know of course the pod is much cheaper, but what’s more?

    • Chris Moore

      You can’t buy that unless you pay to have it configured. Over $8k base and they want you to buy hard drives as part of the build. Not competitive on price.

  • Hi, I want to ask a question: When your techs discovery a hard drive has too many bad sectors, and the hard drive need to replace. There has 45 hard drive in one Storage Pod, how your techs find out whitch hard drive that you should to replace?

  • Tommy B

    Where do i buy the backplanes in Europe? I cant find them on amazon or anywhere else, and I dont know which alternative I can use.


    Hi! What do you think about the 246 usd Seagate Archive HDD v2 8TB?

  • Dr Zahid Shah

    HI, can you throw some light on what OS is these storage pod run? and
    how you inter connect them? i mean with normal LAN or high speed
    gigabit adapter? or something else?
    and 1 more thing, how can i get these parts in India? as its very difficult to ship from U.S that all stuff to India.

  • Mathew Binkley

    We have a couple of petabytes of data, partly on backplane servers, partly on direct-cabled servers. Backplanes make your life easier when a drive fails (which they do with regularity) because you can light up the locate led on a drive and fish it out. Newer backplanes also allow you to power-cycle an individual drive when it blips out due to buggy firmware, so you don’t have to power-cycle your entire server to fix it.

    We haven’t seen a backplane failure yet, and HBA controller failures are rare, but hard drive failures are constant, so it makes sense to optimize for that case.

    Our use case isn’t the same as Backblaze. They seem to be “write once and read occasionally”, while ours drives are constantly being beaten to death (roughly 4 gigabytes of traffic per second over the past week), so our reasons may not be the same as theirs.

    • Chris Rattray

      Hi Mathew, could you elaborate a bit on the type of hardware you’re using? The power-cycle feature seems useful and was not a technology I was aware of.

      • Mathew Binkley

        Our current chassis is a Chenbro RM41736 They do *not* support power on/off.

        Our next server purchases will use an AIC RSC-4BH. The backplane in it *will* support power on/off via the sg_ses command:

        sg_ses –-descriptor=Disk003 – – set=3:4:1 SCSI 3:1,118,0 (AIC SAS expander) – -verbose
        sg_ses – -page=2 SCSI 3:1,118,0 (Check Element 2 …Device off =1 )

        We have a script that uses sg_ses to turn on/off the locate led, so modifying it to power-cycle a drive is just tweaking one line.

  • Can you give exact part number of these backplanes?

    • The part number is the Sunrich S330 of the Marvell SM9715 chipset!

      • Thanks, Yev!
        Surely now I will be able to build much better pod and become your biggest competitor :-) Keep up the good work!

        • Good luck ;-)

          • Geekin things

            Where would one buy the Sunrich S330?

          • FeRD

            That appears to be the million dollar question. The only supplier/distributor any web searches seem to come up with is Arrow, who are quite out of stock. (They’ll give you a backorder quote, for a minimum quantity of 500 units.)

            Even more confounding, the S-330 appears nowhere on Sunrich’s own website!

            It’s as if the thing doesn’t even exist, outside of some Backblaze engineer’s fever dream.

  • karl

    270 TB in one machine is astonishing.
    I wonder how many years it’ll be until there is 1 PB of storage in one box. Storage Pod X

    • Dan

      2 is the answer

      • karl

        That’s precise thanks.

    • Soon as 20TB hard drives hit the market at a reasonable rate…We’ll get close ;-)

  • ticking

    I’d be higly interested in the resoning behind the backplanes as well.
    We have both systems in production, and everybody is looking forward the day the backplane one gets phased out.
    There are a billion less firmware bugs that have to be avoided with the direct approach.

    • Essentially it boiled down to cost management. With the newly available backplanes we were getting great performance in our environment, and it was less expensive than the direct system. Plus our ops team had years of experience with the backplane design, so there’s a nostalgia/level of comfort that they have with it.

  • Can you discuss in more detail why you decided to go back to the backplanes? The 4.0 blog post described the advantages of the direct-wire approach — how do the new backplanes outweigh those advantages? Are the backplanes cheaper, faster, more reliable?

    • Joe, the answer is all three. When we first did 4.0 we were happy with the direct approach, but as time went on, the costs of the backplane components decreased, and their availability increased. At the end of the day it was a business decision though, we had to see whether or not we wanted to continue investing in the 4.0 infrastructure, or given the lower cost and higher availability of the new backplanes, to go back to the system which we had been using for years prior, which had a lower learning curve for our ops team and an overall lower cost.