+1 for the merge.

Thanks a lot to Uma and all contributors working on EC.  Great work!

It's so great that we have EC in Ozone now.

Bests,
Sammi

On Wed, 6 Apr 2022 at 13:59, Uma gangumalla <umamah...@apache.org> wrote:

> Dear Ozone Devs,
>
> As you may know, we have been actively developing Ozone Erasure Coding
> support in a separate branch HDDS-3816-ec.
>
> We have finished the development of EC key write and read functionality.
> The support of offline recovery( Recovering replica from node loss) will be
> part of second phase work.
>
> Since the code has already grown and increasingly started seeing merge
> complications, we would like to propose to merge the current EC branch into
> master.
>
> We filed the new JIRA(HDDS-6462) for the second phase of work and continued
> the offline recovery work there.
>
> Details on Changes:
>
>    -
>
>    Most of the EC core logic went to newly extended classes. Key changes
>    went into EC*OutputStream and EC*InputStream classes for write and read
>    respectively. Based on replication type, ECPipelineProvider will be
> chosen
>    for creating EC pipelines.
>
>
>
>    -
>
>    Since we cannot represent the EC replication in the existing replication
>    factor, we have introduced ECReplicationConfig. The ReplicationConfig
>    interface is already pushed to master, so it’s not a new idea coming
>    through this branch merge now. What is newly coming here is the
>    ECReplicationConfig class which can be used to express EC replication
>    configuration.
>
>
>
>    -
>
>    We wanted to provide the support to enable EC at bucket level. To
>    simplify some complications, we have moved the default replication
>    configurations from client to server.
>
>
>
>    -
>
>    Client side replication type and replication factor removed from the
>    configuration files and introduced the ozone.server.default.replication
>    and ozone.server.default.replication.type.We would continue to respect
> if
>    one configures at client side explicitly or passed through APIs,
> otherwise
>    server side bucket level properties or server side default configuration
>    would take effect.
>
>
>
>    -
>
>    Other than this change, the rest of EC side code should not impact any
>    of the existing code flows.
>
>
> We have finished documentation JIRA(HDDS-6172) for covering this feature
> and we will continue to improve further in master.
>
> Git Branch Name : HDDS-3816-ec
>
> JIRAs: HDDS-3816 and HDDS-5351
>
> Completed tasks: ~ 142
>
> + We are covering the following two mandatory JIRAs:
>
> 1. HDDS-6209: EC: [Forward compatibility issue] New client to older server
> could fail due to the unavailability for client default replication config
>
> 2. HDDS-5909: EC: Onboard EC into upgrade framework.
>
> PRs reviews in-progress and expected to close in a day or two.
>
> Few other JIRAs in HDDS-3816 are still open but I believe they're not
> blockers for merge.
>
> In short what you can do now with this feature:
>
>    -
>
>    You can enable EC at bucket level and cluster level.
>
> How to enable it at bucket level? Just create the bucket by passing the ec
> replication options.
>
>    -
>
>    You can create EC keys and read the same back.
>    -
>
>    You should be able to continue writing even when chosen nodes are
>    failing. (Of Course minimum of Data+Parity live nodes should be
> available
>    in cluster for complete the write)
>    -
>
>    You should be able to read the file back even if a few nodes failed in
>    the same ec block group(Failures should not be more than parity number
> of
>    nodes.).
>
> What is pending? Offline recovery of lost/missing EC containers. As
> mentioned above, post merge of this branch, I will create a separate JIRA
> for starting the work for OfflineRecovery.
>
>
> There are automated acceptance test cases already added. HDDS-6231
>
> In addition to that, we have also performed basic Acceptance Testing in
> physical cluster:
>
>    1.
>
>    Installed 10 nodes cluster and created EC bucket (3:2).
>
> Uploaded 10GB key.
>
> Downloaded the same key and checked the md5sum.
>
>    1.
>
>    Uploaded 8GB key.
>
> Downloaded the same key and checked the md5sum.
>
>    1.
>
>    Uploaded 3MB key
>
> Downloaded the same and verified md5sum.
>
>    1.
>
>    Changed bucket to (6:3)
>
> Uploaded 8GB key
>
> Download the same.
>
> Also verified the new key should be in 6:3 policy and old keys must be
> 3:2.Verified
> with several different size key writes and reads.
>
> Merge checklist items assessment is here:
>
> https://cwiki.apache.org/confluence/display/OZONE/Ozone+EC+Branch%28HDDS-3816-ec%29+Phase-1+%3A+Merge+Checklist
>
> Big shoutout to Stephen O'Donnell <sodonn...@cloudera.com>, Istvan Fajth
> <pi...@cloudera.com> for great efforts in core development and also thanks
> a lot  to Sammi, Mingchao Zhao, Mark Gui, Kaijie for collaborating on some
> of the EC tasks.
>
> Thanks to Marton for design discussion and on some dev tasks as well.
>
> Thanks to many others who were involved in design discussions, Arpit, Sidd,
> Jitendra, Mukul, Sanjay, Karthik, Bharat, Nanda, Shashi, Prashanth, Rakesh,
> Yiqun Lin.
> Sorry if I miss anyone here, but your efforts are much appreciated. Without
> your tremendous help, we would have not reached this position yet.
>
> If there are no objections for the merge, I will start the official vote
> later.
>
> Regards,
>
> EC Branch Devs
>

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