All-
I accidentally ran across a commercial solution that looks like it
would fit the bill for THREDDS on S3, provided you had the funds to spend on it:
http://panzura.com/products/global-file-system/
<http://panzura.com/products/global-file-system/>
http://go.panzura.com/rs/panzura/images/AmazonSolutionBrief.pdf
<http://go.panzura.com/rs/panzura/images/AmazonSolutionBrief.pdf>
> On Jul 14, 2015, at 11:40 PM, David Nahodil <David.Nahodil@xxxxxxxxxxx> wrote:
>
> Hi all,
>
> As you mention mounting S3 as a file system was problematic for a few reasons
> (including the speed issues) which is why we wanted to look into other
> options.
>
> I had come across the work NOAA/OpenDAP work on Hyrax which was interesting,
> and might still be a fall-back depending on how my investigations go. I
> hadn't seen that paper though (thanks James) and that was a good summary of
> the work and findings.
>
> There are other considerations and techniques which I am still learning about
> with AWS. It might still be the case that we need to use EBS in conjunction
> with S3.
>
> John's point about the file system operations to provide the random access
> required is an important one. If I understand correctly it, the Hyrax work
> kept a local cache of files as they were needed. This local caching
> populating from S3 might be the technique we need to employ. It's a pain to
> manage resources like that (disk size, cache invalidation, etc.), though, so
> we'll have to see.
>
> I made a bit of progress today fleshing-out a CrawlableDataset, I expect to
> come up against a few more challenges tomorrow.
>
> Thanks all for the input!
>
> Cheers,
>
> David
>
>
>
>
>
> ________________________________________
> From: Nathan Potter <gnatman.p@xxxxxxxxx>
> Sent: Wednesday, 15 July 2015 8:17 AM
> To: Jeff McWhirter
> Cc: Nathan Potter; Robert Casey; John Caron; David Nahodil;
> thredds@xxxxxxxxxxxxxxxx
> Subject: Re: [thredds] THREDDS Data Server serving from Amazon S3
>
> Jeff,
>
> I would also add that because of the time costs associated with retrieving
> from Glacier it becomes crucial to only get what you really want. To that end
> I believe that such a system can only work well if the granule metadata (and
> probably any shared dimensions or Map vectors) be cached outside of Glacier
> so that users can retrieve these information without having to incur the time
> and fiscal expense of a full Glacier retrieval.
>
> In DAP parlance the DDS/DAS/DDX/DMR responses should be immediately available
> for all holdings. And I think that Map vectors/dimension should also be
> included in this. This would go a long way towards making such a system
> useful to a savvy client.
>
>
> N
>
>> On Jul 14, 2015, at 2:52 PM, Nathan Potter <ndp@xxxxxxxxxxx> wrote:
>>
>>
>>
>> Jeff,
>>
>> I wrote some prototypes for Hyrax that utilized Glacier/S3/EBS to manage
>> data. It was a proof of concept effort - not production ready by any means.
>> It seems your idea was very much in line with my own. My thinking was to put
>> EVERYTHING in Glacier and then spool things off Glacier into S3, and then
>> from there into EBS as needed by the server. Things would get spooled from
>> Glacier to S3 and then copied into an EBS volume for operational access.
>> Last accessed content would get purged, first from EBS and then later from
>> S3 so that eventually the only copy would be in Glacier, at least until the
>> item was accessed again. I think it would be really interesting to work up a
>> real system that does this for DAP services of science data!
>>
>> Our experience with S3 filesystems was similar to Roy’s: The various S3
>> filesystem solutions that we looked at did’t really cut it (speed &
>> proprietary utilization of S3). But managing S3 isn’t that tough, I skipped
>> the filesystem approach and just used the AWS HTTP API for S3 and it was
>> quick and easy. Glacier is more difficult: Access times are long for
>> everything. That includes 4 hours to get an inventory report, despite the
>> fact that the inventory is computed by AWS once every 24 hours. So managing
>> the Glacier holdings by keeping local copies of the inventory is important
>> as is having a way to verify that the local inventory stays in sync with the
>> actual inventory.
>>
>>
>> Nathan
>>
>>> On Jul 14, 2015, at 1:00 PM, Jeff McWhirter <jeff.mcwhirter@xxxxxxxxx>
>>> wrote:
>>>
>>>
>>> Glacier could be used for storage of all that data that you need to keep
>>> around but rarely if ever access - e.g., level-0 instrument output, raw
>>> model output, etc. If your usage model supports this type of latency then
>>> the cost savings (1/10th) are significant
>>>
>>> This is where hiding the storage semantics behind a file system breaks
>>> down. The application can't be agnostic of the underlying storage as they
>>> need to support delays in staging data, communicating to the end-user,
>>> caching, etc.
>>>
>>> -Jeff
>>>
>>>
>>>
>>> On Tue, Jul 14, 2015 at 1:35 PM, Robert Casey <rob@xxxxxxxxxxxxxxxxxxx>
>>> wrote:
>>>
>>> Hi Jeff-
>>>
>>> Of note, Amazon Glacier is meant for infrequently needed data, so a
>>> call-up for data from that source will require something on the order of a
>>> 5 hour wait to retrieve to S3. I think they are developing a near-line
>>> storage solution that is a bit more expensive to compete with Google's new
>>> near-line storage, which provides retrieval times on the order of seconds.
>>>
>>> -Rob
>>>
>>>> On Jul 14, 2015, at 10:10 AM, Jeff McWhirter <jeff.mcwhirter@xxxxxxxxx>
>>>> wrote:
>>>>
>>>> On this note -
>>>> What I really want is a file system that can transparently manage data
>>>> between primary (SSD), secondary (S3) and tertiary (Amazon Glacier)
>>>> stores. Actively used data would migrate into primary storage. Old
>>>> archived data moves off into cheaper tertiary storage. I've thought of
>>>> implementing this at the application level in RAMADDA but a file system
>>>> based approach would be much smarter.
>>>>
>>>> How do the archive folks on this list manage these kinds of storage
>>>> environments?
>>>>
>>>> -Jeff
>>>>
>>>>
>>>>
>>>>
>>>> On Tue, Jul 14, 2015 at 10:44 AM, John Caron <caron@xxxxxxxx> wrote:
>>>> Hi David:
>>>>
>>>> At the bottom of the TDM, we rely on RandomAccessFile. Do you know if S3
>>>> supports that abstraction (essentially posix file semantics, eg seek(),
>>>> read()) ? My guess is that S3 only allows complete file transfers (?)
>>>>
>>>> Would be worth investigating if anyone has implemented a java
>>>> FileSystemProvider for S3.
>>>>
>>>> Will have a closer look when i get time.
>>>>
>>>> John
>>>>
>>>> On Mon, Jul 13, 2015 at 7:59 PM, David Nahodil <David.Nahodil@xxxxxxxxxxx>
>>>> wrote:
>>>> Hi all,
>>>>
>>>>
>>>> We are looking at moving our THREDDS Data Server to Amazon EC2 instances
>>>> with the data hosted on S3. I'm just wondering if anyone has tried using
>>>> TDS with data hosted on S3?
>>>>
>>>>
>>>> I had a quick back-and-forth with Sean at Unidata (see below) about this.
>>>>
>>>>
>>>> Regards,
>>>>
>>>>
>>>> David
>>>>
>>>>
>>>>>> Unfortunately, I do not know of anyone who has done this, although we
>>>>>> have had at lease one other person ask. From what I understand, there is
>>>>>> a way to mount an S3 storage as a virtual file system, in which case I
>>>>>> would *think* that the TDS would work as it normally does (depending on
>>>>>> the kind of data you have).
>>>>
>>>>> We have considered mounting the S3 storage as a filesystem and running it
>>>>> like that. However, our feeling was that the tools were not really
>>>>> production ready and that we're really misrepresenting S3 by pretending
>>>>> it is a file system. So this is why we're investigating if anyone has
>>>>> used TDS with the S3 API directly.
>>>>
>>>>>> What kind of data do you have? Will your TDS also be in the cloud? Do
>>>>>> you plan on serving the data inside of amazon to other EC2 instances, or
>>>>>> do you plan on crossing the cloud/commodity web boundary with the data,
>>>>>> in which case that could get very expensive quite quickly?
>>>>
>>>>> We have about 2 terabytes of marine and climate data that we are
>>>>> currently serving from our existing infrastructure. The plan is to move
>>>>> the infrastructure to Amazon Web Services so TDS would be hosted on EC2
>>>>> machines and the data on S3. We're hoping this setup should work okay,
>>>>> but we might still have a hurdle or two to come. :)
>>>>
>>>>> We have someone here who once wrote a plugin/adapter for TDS to work with
>>>>> an obscure filesystem that our data used to be stored on. So we have a
>>>>> little experience in what might be involved in what might be involved for
>>>>> doing the same with S3. We just wanted to make sure that if anyone had
>>>>> done some work already that we made use of that.
>>>>
>>>>>> We very, very recently (as in a day ago) got some Amazon resources to
>>>>>> play around on, but we won't have a chance to kick those tires until
>>>>>> after our training workshops at the end of the month.
>>>>
>>>>
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>>>>
>>>>
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>>>
>>>
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>>
>> = = =
>> Nathan Potter ndp at opendap.org
>> OPeNDAP, Inc. +1.541.231.3317
>>
>
> = = =
> Nathan Potter ndp at opendap.org
> OPeNDAP, Inc. +1.541.231.3317
>
>
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