Re: rbd STDIN import does not work / wip-rbd-export-stdout

[Dan Mick <dan.mick@inktank.com>]

It writes zeros; there's no way for it to know how many zeros are 
coming.  It could make a half-hearted attempt depending on its buffer 
size and the amount of data the source is willing to buffer.

As for fstrim: on the rbd image?....sure, if it's a filesystem, it ought 
to work (modulo some bugs I've heard about with 32-bit vs. 64-bit 
offsets in qemu... :) )


On 11/26/2012 11:35 AM, Stefan Priebe - Profihost AG wrote:
> Hi,
>
> Export isn't a problem. But import should handle this correctly. Or does it  write zeros to the object file
>
> But even if it write zeros to the file shouldn't a fstrim fix this?
>
> Stefan
>
> Am 26.11.2012 um 18:34 schrieb Dan Mick <dan.mick@inktank.com>:
>
>> Yes, it's broken too (there's an issue open on it). I have some test
>> code done over the weekend
>> and will be pushing it after review.
>>
>> Be aware that import/export to stdin/stdout are limited in that they
>> cannot preserve sparseness
>> of the image, but they should both be working soon at least.
>>
>> On Mon, Nov 26, 2012 at 5:35 AM, Stefan Priebe - Profihost AG
>> <s.priebe@profihost.ag> wrote:
>>> Am 26.11.2012 14:29, schrieb Oliver Francke:
>>>>
>>>> Well...
>>>
>>>
>>> makes no difference:
>>> gzip -dc vm-101-disk-1.img.gz | rbd import --format=2 --size=40960 -
>>> kvmpool1/vm-101-disk-1
>>>
>>> rbd: error reading file: (29) Illegal seek
>>> Importing image: 0% complete...failed.
>>> rbd: import failed: (29) Illegal seek
>>>
>>> I think the problem is that ceph seeks in File when it get's zeros (not
>>> filled content). But seeking doesn't work on stdin. It has to read from
>>> stdin until there are no more zeros.
>>>
>>> Stefan
>>>
>>>
>>>> On 11/26/2012 02:20 PM, Stefan Priebe - Profihost AG wrote:
>>>>>
>>>>> Hello list,
>>>>>
>>>>> i know branch wip-rbd-export-stdout is work in progress but it is more
>>>>> than useful ;-)
>>>>>
>>>>> When i try to import an image i get:
>>>>>
>>>>> # gzip -dc vm-101-disk-1.img.gz | rbd import --format=2
>>>>> --size=42949672960 - kvmpool1/vm-101-disk-1
>>>>> rbd: error reading file: (29) Illegal seek
>>>>> Importing image: 0% complete...failed.
>>>>> rbd: import failed: (29) Illegal seek
>>>>>
>>>>> Anything i've tried wrong?
>>>>
>>>>
>>>> I would assume, that size is already in MiB? Seems to be a slightly too
>>>> big value... Not tried myself, though...
>>>>
>>>> Oliver.
>>>>
>>>>>
>>>>> Greets,
>>>>> Stefan
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