[SATLUG] 67 TB for less than $8K

Bruce Dubbs bruce.dubbs at gmail.com
Tue Oct 9 22:03:48 CDT 2012


Brad Knowles wrote:
> On Oct 9, 2012, at 6:16 PM, Bruce Dubbs <bruce.dubbs at gmail.com>
> wrote:
>
>> I'm not going to build one of these things because I don't need it,
>> but I would suggest it to an employer with a limited budget but a
>> need for a large amount of disk space to try out and develop actual
>> experience with the concept from both a technical point of view and
>> from a cost perspective.
>
> Here's a good page on the subject:
> <http://bioteam.net/2011/08/why-you-should-never-build-a-backblaze-pod/>.
>
>  Quoting from this page:
>
>> What are the risks?

You forgot some parts:

This section is meant to be tongue-in-cheek since it should be clear by 
now that we have actually gone out and built one of these things (and 
had a blast doing it, pictures to follow …).

>> The backblaze storage pod was designed for a very specific use case
>> that is not a great fit for more generic usage. A quick glance at
>> the design plans will tell you:
>>
>> • The system uses a single disk for hosting the operating system

Setting up a RAID wouldn't be hard.

• The system requires 2 power supplies to operate, both must be
   active and there is no redundancy, spare or failover unit

True

• The system has no hardware RAID capability

What does HW RAID offer over SW RAID?  It may offer better HW, but there 
isn't a difference between a program loaded out of firmware or off a 
disk.  I slightly better MB with more PCIe slots or evne a good on-board 
RAID capability would fix that.

• The system only has 2 GigE network interfaces

That can be fixed with not too expensive HW.

• To access/replace a disk drive you need to remove 12 screws

Yes, that sounds like a pain if you have to do this very frequently.

• To access/replace a disk drive you need to remove the top cover

If you only have one or two, it's really not that much of an issue.  For 
a data center with lots of rack, it would be an issue.

• If you build this yourself totally DIY you
   will be required to create custom wiring harnesses

It is a DIY project.

• Any monitoring or health status reporting tools will have
  to be built, installed and configured by hand

When we designed and built a jet engine testing system for the Air Force 
(TF-39, F-100, Gas Turbines), we did that and a lot more.  Using 
government engineers saved is 10's of millions of (1985) $ and it was 
better than anything the commercial marketplace had to offer.

Been there, done that.

We did have lots of computing power.  HP A-Series A700: 16-bit, 3MHz, I 
don't recall the amount of memory.  :)

http://www.strobedata.com/home/rmkca.html

>> Simply put this box has no “highly
>> available” features and any sort of significant maintenance on it
>> will almost certainly require the  system to be taken offline and
>> possibly even powered down. You also need to mount this unit on
>> extremely heavy-duty rack rails OR put it on a shelf and leave
>> about 12 inches of top clearance free if you want to easily be able
>> to pop the top cover off to get at the drives.

May or may not be reasonable.

>> This is cheap storage, not fast storage and certainly not
>> highly-available storage. It carries a far higher operational and
>> administrative burden than storage arrays traditionally sold into
>> the enterprise.

At a far lower price.  If you want everything done for you, you have to 
pay big bucks.

   - Bruce


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