[Openstack] [Swift] Unexplained 404s
shrinand at maginatics.com
Mon May 23 20:49:44 UTC 2016
Thanks John, Mark,
I'll try these steps.
If objects are placed on different devices than the computed ones,
they will be unavailable until the replication places them at the
correct location. And this could take a really long time. Is that
On Fri, May 20, 2016 at 4:53 PM, Mark Kirkwood
<mark.kirkwood at catalyst.net.nz> wrote:
> On 21/05/16 05:27, Shrinand Javadekar wrote:
>> I am troubleshooting a test setup where Swift returned a 201 for
>> objects that were put in it but later when I tried to read it, I got
>> back 404s.
>> The system has been under load. I see lots of connection errors,
>> lock-timeouts, etc. However, I am not sure if ever Swift should be
>> returning a 404.
>> I tried simulating some of these on a different setup and always got
>> the expected response (which wasn't a 404).
>> - Stopped memcached and did a blob get. This returned a 401 Unauthorized
>> - Stopped the object-server and did a blob get. This returned a 503
>> internal server error.
>> - Stopped the container-server. This didn't have any effect. The
>> container-server is not looked during every GET.
>> - Stopped the account-server. Same result as container-server.
>> Any ideas on when Swift might return a 404 even though the object was
>> successfully written?
> I addition to what John said, I've seen that sort of behaviour on slow or
> heavily loaded systems (e.g):
> - write an object (successful)
> - immediately try to read it (404)
> - a few minutes later try to read it (successful)
> This is because the replication step can take some time to place the object
> on all the devices where it is supposed to live (i.e a read may not always
> look at where the object has just been written).
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