Thanks for the detailed explanation. +1 to merge with HDDS-6209 addressed.
> On Feb 16, 2022, at 10:49 AM, Uma gangumalla <umamah...@apache.org> wrote: > > Thanks a lot Arpit for your feedback. > > [Arpit Wrote] - New client writing to old server with 3-way and 1-way > replication. > [Uma] As mentioned in the proposal mail, we have a forward > compatibility issue (HDDS-6209) as we have removed the client side default > configurations. One that is in, this should work. > We will make sure to get this in before merge. > > [Arpit Wrote] - Old client writing to new server in bucket without EC > policy [both 1-way and 3-way] > [Uma] Old client alway passed the replication configs. Irrespective of > bucket policy, we respect client passed replication config. so, this is > fine. > > [Arpit Wrote] - Old client writing to new server in bucket with EC policy > [both 1-way and 3-way] > [Uma] As mentioned above, Old clients always passed non ec replication > options while creating keys. Even when a call comes to the EC policy > bucket, we allow non EC keys to be created on EC buckets. > > Also when a newer client writing EC option keys on an old server would be > rejected. That should be covered as part of HDDS-6209. We are using a > server, client versioning mechanism to detect the old server which cannot > support EC. > > @Pifta, you may want to add your thoughts if any? > > Regards, > Uma > > On Wed, Feb 16, 2022 at 8:23 AM Arpit Agarwal <aagar...@cloudera.com.invalid> > wrote: > >> Thanks Uma for starting this discussion. Excited to see EC support for >> Ozone coming together at last. >> >> We should verify the the compatibility matrix prior to merge: >> >> - New client writing to old server with 3-way and 1-way replication. >> - Old client writing to new server in bucket without EC policy [both 1-way >> and 3-way] >> - Old client writing to new server in bucket with EC policy [both 1-way >> and 3-way] >> >> >> Arpit >> >> >>> On Feb 15, 2022, at 12:17 AM, 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 will file the new JIRA for the second phase of work and continue 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. >>> >>> JIRA: HDDS-3816 >>> >>> Completed tasks: ~ 90 >>> >>> We wanted to cover the following compatibility issue before the merge: >>> >>> HDDS-6209: EC: [Forward compatibility issue] New client to older server >>> could fail due to the unavailability for client default replication >> config >>> >>> 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. >>> >>> >>> >>> 1. >>> >>> 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 >> >> >> --------------------------------------------------------------------- >> To unsubscribe, e-mail: dev-unsubscr...@ozone.apache.org >> For additional commands, e-mail: dev-h...@ozone.apache.org >> >> --------------------------------------------------------------------- To unsubscribe, e-mail: dev-unsubscr...@ozone.apache.org For additional commands, e-mail: dev-h...@ozone.apache.org
