Open Stack

I'm not familiar with that format, but in general, if you're dealing with large objects, you can get better performance by splitting the data in the client, uploading each separate segment concurrently, and then creating a large object manifest to tie the segments together (allowing future access by either segments or as a logical whole).

https://docs.openstack.org/swift/latest/overview_large_objects.html#module-swift.common.middleware.slo

--John




On 5 Oct 2017, at 11:24, Jialin Liu wrote:

> Thank you John,
>
> I think I figured out the way. My case is a little bit rare as I'm dealing
> with the HDF5 file format, I can not think of any way to retrieve the
> entire in memory file as a single python object and then serialize it.
> What I did is to use the hdf5.get_file_image function to get a memory image
> of the file, and then use, io.ByteIO(image) to make it a file-like object.
>
> So far, it works well, but I believe it is not the best way in terms of
> performance.
>
> Best,
> Jialin
>
> On Thu, Oct 5, 2017 at 8:25 AM, John Dickinson <me at not.mn> wrote:
>
>> If you've got an arbitrary object in Python, you'll need to serialize it
>> to a file-like object. You could keep it in memory and use a StringIO
>> type, or you could serialize it to disk and open() it like any other file.
>>
>> Ultimately, Swift is storing arbitrary bytes and doesn't care what they
>> are. You, as the Swift client (i.e. API user), need to dump those bytes on
>> the network to send them to Swift. As long as you're transforming your
>> Python object[s] in some regular way that makes sense in your application,
>> it doesn't matter what bytes you send to Swift.
>>
>> --John
>>
>> On 5 Oct 2017, at 8:07, Jialin Liu wrote:
>>
>> Hi,
>> It seems to me that openstack swift only supports file upload/download, is
>> it possible to put a python object to swift store?
>> The doc says we could use file-like object, e.g., StringIO, but this is
>> very limited. I'd like to write a numpy array or other python object into
>> the swift store, can anybody tell me the solution?
>>
>> Best,
>> Jialin
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