[HOT] Optimal NAS tech specifications to serve imagery tiles

john whelan jwhelan0112 at gmail.com
Wed Mar 22 18:23:48 UTC 2017


The other issue is reliability.  On a NAS device you have more than one
hard drive.  If any of them fail it gets interesting.  Expensive hot
swappable NAS devices just slowdown but you do need someone to open the box
and replace the drive with one of I'll say exactly the same model.  Not a
job for an untrained person.

Worse case would be my Dell machine.  It has RAID 1 but until the defective
drive is replaced and the RAID has rebuilt itself the machine cannot be
used.

SSDs do offer higher reliability some Samsung drives have MTBFs of ten
years or more.  Another alternative perhaps?

Regret asking a techie an apparently simple question yet?

Cheerio John

On 22 Mar 2017 1:56 pm, "john whelan" <jwhelan0112 at gmail.com> wrote:

> Realistically do you need the complexity and expense of NAS?  Most hard
> drives last at least two years, Western Digital traditionally last a bit
> longer in general.  Drives with a 5 year warranty are available so I'd
> think in terms of an external hard drive with a USB 3 connector.
>
> Windows does a fair job of caching so max the memory on the lap top fairly
> cheap these days and plug in an external drive.  Translation we measure
> hard drive response times in milliseconds memory in nanoseconds. 10 to the
> minus 3 and 10 to the minus 9.  No matter how fast a hard drive is its way
> behind memory speed wise.  Typically hard drives and NAS have memory caches
> to speed up access time but basically physical devices are slow.
>
> I suggest a WiFi separate router for the WiFi network but most lap tops
> can function as a WiFi hot spot.  Jut put it on a shelf to give it a bit
> more range.
>
> I think Google runs on second hand drives.
>
> You are basically reading from the hard drive and unless you have a
> hundred or so people wanting to load images at exactly the same time you
> should be fine on a single drive.  People work at different rates and a
> couple of tiles will often keep them happy for ten minutes.  Use Windows
> backup to backup the captured data every evening or more often if you feel
> necessary.
>
> Cheerio John
>
> On 22 March 2017 at 13:21, Claire Halleux <claire.halleux at hotosm.org>
> wrote:
>
>> Hello John and Joseph,
>>
>> Thank you for your inputs and reactivity.
>> I was initially looking for suggested hardware, but advices on how to
>> better do it will be welcome too.
>>
>> Going for a NAS configured as RAID1 would solve the need of redundancy.
>> However, if going for an Intel NUC, we would simply back up our images
>> elsewhere anyway.
>> Between the two (or more options), we are investigating what would give
>> the OSM contributors the best user experience (that would likely be = which
>> one would serve the tiles in the fastest way).
>>
>> Cheers
>>
>> Claire
>>
>>
>>
>> On Wed, Mar 22, 2017 at 5:53 PM, john whelan <jwhelan0112 at gmail.com>
>> wrote:
>>
>>> Taking it a step further thinking in terms of the camps since the design
>>> almost certainly includes WiFi could a basic store and forward message or
>>> email system be included?  Most emails are probably local and phone data
>>> costs are expensive, you might get swamped with video attachments though.
>>>
>>> Commotion could be used to build a small network to cover the camps or
>>> village.
>>>
>>> Cheerio John
>>>
>>> On 22 Mar 2017 12:39 pm, "Dale Kunce" <dale.kunce at gmail.com> wrote:
>>>
>>>> I forgot to mention that we are spending a lot of time to update and
>>>> get better documentation on POSM out there. Just this week we started to
>>>> work on the content for a better website. The site is not complete and many
>>>> things will be changing but it will give you a good idea of the content we
>>>> are creating. If you have any suggestions please file the issues here
>>>> https://github.com/posm/posm.io/issues
>>>>
>>>> https://posm.github.io/posm.io/
>>>>
>>>>
>>>>
>>>> On Wed, Mar 22, 2017 at 9:34 AM, Dale Kunce <dale.kunce at gmail.com>
>>>> wrote:
>>>>
>>>>> POSM was developed exactly for this type of use case. The status.md
>>>>> isn't up to date and should be ignored.
>>>>>
>>>>> POSM does host imagery with the new OpenDroneMap module. You can add a
>>>>> tiff and it will be served as a TMS. You an also add any MBTile archive
>>>>> (bing) and have that served as well. POSM is designed to take an AOI, use
>>>>> collected imagery, host field papers, and have support for mobile data
>>>>> surveys all offline.
>>>>>
>>>>> Happy to answer any questions that anyone might have.
>>>>>
>>>>> Dale
>>>>>
>>>>>
>>>>> On Wed, Mar 22, 2017 at 9:08 AM, Joseph Reeves <iknowjoseph at gmail.com>
>>>>> wrote:
>>>>>
>>>>>> Thanks John, but I'm mostly certain POSM doesn't host imagery:
>>>>>> https://github.com/posm/posm/blob/master/STATUS.md
>>>>>>
>>>>>> Looks like it could be a good feature to add though! Looks like Dale
>>>>>> has opened an issue on it already: https://github.com/po
>>>>>> sm/posm/issues/277
>>>>>>
>>>>>> Cheers, Joseph
>>>>>>
>>>>>>
>>>>>>
>>>>>> On 22 March 2017 at 15:58, john whelan <jwhelan0112 at gmail.com> wrote:
>>>>>>
>>>>>>> ​an old post giving details.
>>>>>>>
>>>>>>> John​
>>>>>>>
>>>>>>> Matt Sayler <matt.sayler at gmail.com>
>>>>>>> 15/08/2016
>>>>>>> to me, Laura, hot
>>>>>>> POSM & Red Cross had an excellent presentation at SOTMUS, and Seth
>>>>>>> mentioned he'd be willing to set some up for the cost of hardware and
>>>>>>> brownies (I assume that will become dependent on demand/appetite):
>>>>>>> http://stateofthemap.us/2016/field-mapping-at-scale/
>>>>>>>
>>>>>>>
>>>>>>> Nutshell: POSM is for mapping in low/no service areas. It can serve
>>>>>>> as a local, disconnected OSM server, which can later push changes up to the
>>>>>>> main OSM when in an area with service. They primarily use Intel NUC's
>>>>>>> (~$350 for all hardware, runs off ~6w), but have installed it on Rasberry
>>>>>>> Pi, Intel Edison, Beagle Bone, etc. I'm not aware of them doing a usb
>>>>>>> bootable install, but might be possible? Red Cross uses $50 Android phones
>>>>>>> & Field Papers for doing the mapping.
>>>>>>>
>>>>>>> Pretty freaking cool project!
>>>>>>>
>>>>>>> https://github.com/AmericanRedCross/posm
>>>>>>>
>>>>>>> On 22 March 2017 at 11:53, Joseph Reeves <iknowjoseph at gmail.com>
>>>>>>> wrote:
>>>>>>>
>>>>>>>> > In a windows environment its fairly easy to configure.  In the
>>>>>>>> security tabs for the folder you just make the folder shareable but read
>>>>>>>> only.
>>>>>>>>
>>>>>>>> There's OSM editors that will source imagery over SMB? I've never
>>>>>>>> looked into it, but I'd be surprised.
>>>>>>>>
>>>>>>>> Thinking about this very quickly, my points would be:
>>>>>>>>
>>>>>>>> 1: RAID: I'd want some disk redundancy as the device is likely to
>>>>>>>> be used in tough environments that are far from good sources of replacement
>>>>>>>> disks, or replacement imagery.
>>>>>>>> 2: Software: As already mentioned, you're going to need some
>>>>>>>> software to serve the tiles. WMS? You'd want a device that was easy to get
>>>>>>>> running with third party software. Performance may also be an issue,
>>>>>>>> depending on how many people you were catering for.
>>>>>>>>
>>>>>>>> I hope someone will come along with an example of what they've
>>>>>>>> managed to do before. If not it should be a fun exercise :)
>>>>>>>>
>>>>>>>> Cheers, Joseph
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>> On 22 March 2017 at 15:42, john whelan <jwhelan0112 at gmail.com>
>>>>>>>> wrote:
>>>>>>>>
>>>>>>>>> Are you looking for information on how to do it?  On suggested
>>>>>>>>> hardware?
>>>>>>>>>
>>>>>>>>> Essentially for this purpose I see no reason why one local machine
>>>>>>>>> such as a lap top couldn't feed the others.  In a windows environment its
>>>>>>>>> fairly easy to configure.  In the security tabs for the folder you just
>>>>>>>>> make the folder shareable but read only.
>>>>>>>>>
>>>>>>>>> Have you  looked at POSM?  (Portable OSM) they may have this
>>>>>>>>> already worked out and documented for the field.
>>>>>>>>>
>>>>>>>>> Thanks John
>>>>>>>>>
>>>>>>>>> On 22 March 2017 at 11:22, Claire Halleux <
>>>>>>>>> claire.halleux at hotosm.org> wrote:
>>>>>>>>>
>>>>>>>>>> Hello HOT Community,
>>>>>>>>>>
>>>>>>>>>> I'm currently looking into NAS specifications for serving imagery
>>>>>>>>>> tiles locally for OSMapping purposes. The NAS would be coupled to a router
>>>>>>>>>> accessible to the mappers. Contributors would still be connected to the
>>>>>>>>>> relatively slow Internet for downloading/uploading their data but the idea
>>>>>>>>>> is to get the ability to load imagery tiles much faster and access
>>>>>>>>>> additional images, in particular during mapathons.
>>>>>>>>>>
>>>>>>>>>> Therefore I would welcome any feedback from people, organisations
>>>>>>>>>> or communities using similar hardware to support data digitizing.
>>>>>>>>>>
>>>>>>>>>> Thank you!
>>>>>>>>>>
>>>>>>>>>> Claire
>>>>>>>>>>
>>>>>>>>>> Claire Halleux
>>>>>>>>>> +243 81 611 6998 (Kinshasa, DRC)
>>>>>>>>>> OpenStreetMap RDC
>>>>>>>>>>
>>>>>>>>>> _______________________________________________
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>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>
>>>>>>>>> _______________________________________________
>>>>>>>>> HOT mailing list
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>>>>>>>>>
>>>>>>>>
>>>>>>>
>>>>>>
>>>>>> _______________________________________________
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>>>>>>
>>>>>
>>>>>
>>>>> --
>>>>> sent from my mobile device
>>>>>
>>>>> Dale Kunce
>>>>> http://normalhabit.com
>>>>>
>>>>>
>>>>
>>>>
>>>> --
>>>> sent from my mobile device
>>>>
>>>> Dale Kunce
>>>> http://normalhabit.com
>>>>
>>>>
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>>
>
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