[openstack-dev] [Openstack] [Swift] Erasure coding reconstructor doesn't work

Luse, Paul E paul.e.luse at intel.com
Tue Jul 21 21:28:55 UTC 2015

I was about to ask that very same thing and, at the same time, if you can indicate if you’ve seen errors in any logs and if so please provide those as well.  I’m hoping you just didn’t delete the hashes.pkl file though ☺


From: Clay Gerrard [mailto:clay.gerrard at gmail.com]
Sent: Tuesday, July 21, 2015 2:22 PM
To: OpenStack Development Mailing List (not for usage questions)
Subject: Re: [openstack-dev] [Openstack] [Swift] Erasure coding reconstructor doesn't work

How did you "deleted one data fragment"?

Like replication the EC consistency engine uses some sub directory hashing to accelerate replication requests in a consistent system - so if you just rm a file down in an hashdir somewhere you also need to delete the hashes.pkl up in the part dir (or call the invalidate_hash method like PUT, DELETE, POST, and quarantine do)

Every so often someone discusses the idea of having the auditor invalidate a hash after "long enough" or take some action on empty hashdirs (mind the races!) - but its really only an issue when someone delete's something by hand so we normally manage to get distracted with other things.


On Tue, Jul 21, 2015 at 1:38 PM, Changbin Liu <changbin.liu at gmail.com<mailto:changbin.liu at gmail.com>> wrote:

To test the latest feature of Swift erasure coding, I followed this document (http://docs.openstack.org/developer/swift/overview_erasure_code.html) to deploy a simple cluster. I used Swift 2.3.0.

I am glad that operations like object PUT/GET/DELETE worked fine. I can see that objects were correctly encoded/uploaded and downloaded at proxy and object servers.

However, I noticed that swift-object-reconstructor seemed don't work as expected. Here is my setup: my cluster has three object servers, and I use this policy:

policy_type = erasure_coding
name = jerasure-rs-vand-2-1
ec_type = jerasure_rs_vand
ec_num_data_fragments = 2
ec_num_parity_fragments = 1
ec_object_segment_size = 1048576

After I uploaded one object, I verified that: there was one data fragment on each of two object servers, and one parity fragment on the third object server. However, when I deleted one data fragment, no matter how long I waited, it never got repaired, i.e., the deleted data fragment was never regenerated by the swift-object-reconstructor process.

My question: is swift-object-reconstructor supposed to be "NOT WORKING" given the current implementation status? Or, is there any configuration I missed in setting up swift-object-reconstructor?



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