Sorry Leo, That’s completely impossible to guess :-D
Factors include - I/O, Network cards, network switch, selinux, block size, CPU, size of objects, number of objects, CRDT, Riak version, etc… Best, Bryan > On 19 Sep 2017, at 18:53, Leo <scicompl...@gmail.com> wrote: > > Dear Bryan, > > Thank you very much for your answers. They are very helpful to me. > I will use more nodes (>=5) in future. > > From your experience with using Riak, what would your guess be for the > time taken to finish all the AAE transfers and be done with the > recovery for about 1 TB worth of data (assuming my cluster is > otherwise completely idle without any user accessing the cluster > during this process and that I am continuously watching the transfers > and re-enabling disabled AAE trees gradually )? I am just asking for > rough estimate from your past experience ( please quote from your > experience with a difference sized cluster / data size too ). My guess > is that it will take approx. 2 days or more. Do you concur? > > Thanks, > Leo > > > On Tue, Sep 19, 2017 at 12:41 PM, Bryan Hunt > <bryan.h...@erlang-solutions.com> wrote: >> (0) Three nodes are insufficient, you should have 5 nodes >> (1) You could iterate and read every object in the cluster - this would also >> trigger read repair for every object >> (2) - copied from Engel Sanchez response to a similar question April 10th >> 2014 ) >> >> * If AAE is disabled, you don't have to stop the node to delete the data in >> the anti_entropy directories >> * If AAE is enabled, deleting the AAE data in a rolling manner may trigger >> an avalanche of read repairs between nodes with the bad trees and nodes >> with good trees as the data seems to diverge. >> >> If your nodes are already up, with AAE enabled and with old incorrect trees >> in the mix, there is a better way. You can dynamically disable AAE with >> some console commands. At that point, without stopping the nodes, you can >> delete all AAE data across the cluster. At a convenient time, re-enable >> AAE. I say convenient because all trees will start to rebuild, and that >> can be problematic in an overloaded cluster. Doing this over the weekend >> might be a good idea unless your cluster can take the extra load. >> >> To dynamically disable AAE from the Riak console, you can run this command: >> >>> riak_core_util:rpc_every_member_ann(riak_kv_entropy_manager, disable, [], >> 60000). >> >> and enable with the similar: >> >>> riak_core_util:rpc_every_member_ann(riak_kv_entropy_manager, enable, [], >> 60000). >> >> That last number is just a timeout for the RPC operation. I hope this >> saves you some extra load on your clusters. >> >> (3) That’s going to be : >> (3a) List all keys using the client of your choice >> (3b) Fetch each object >> >> https://www.tiot.jp/riak-docs/riak/kv/2.2.3/developing/usage/reading-objects/ >> >> https://www.tiot.jp/riak-docs/riak/kv/2.2.3/developing/usage/secondary-indexes/ >> >> >> >> >> >> >> >> On 19 Sep 2017, at 18:31, Leo <scicompl...@gmail.com> wrote: >> >> Dear Riak users and experts, >> >> I really appreciate any help with my questions below. >> >> I have a 3 node Riak cluster with each having approx. 1 TB disk usage. >> All of a sudden, one node's hard disk failed unrecoverably. So, I >> added a new node using the following steps: >> >> 1) riak-admin cluster join 2) down the failed node 3) riak-admin >> force-replace failed-node new-node 4) riak-admin cluster plan 5) >> riak-admin cluster commit. >> >> This almost fixed the problem except that after lots of data transfers >> and handoffs, now not all three nodes have 1 TB disk usage. Only two >> of them have 1 TB disk usage. The other one is almost empty (few 10s >> of GBs). This means there are no longer 3 copies on disk anymore. My >> data is completely random (no two keys have same data associated with >> them. So, compression of data cannot be the reason for less data on >> disk), >> >> I also tried using the "riak-admin cluster replace failednode newnode" >> command so that the leaving node handsoff data to the joining node. >> This however is not helpful if the leaving node has a failed hard >> disk. I want the remaining live vnodes to help the new node recreate >> the lost data using their replica copies. >> >> I have three questions: >> >> 1) What commands should I run to forcefully make sure there are three >> replicas on disk overall without waiting for read-repair or >> anti-entropy to make three copies ? Bandwidth usage or CPU usage is >> not a huge concern for me. >> >> 2) Also, I will be very grateful if someone lists the commands that I >> can run using "riak attach" so that I can clear the AAE trees and >> forcefully make sure all data has 3 copies. >> >> 3) I will be very thankful if someone helps me with the commands that >> I should run to ensure that all data has 3 replicas on disk after the >> disk failure (instead of just looking at the disk space usage in all >> the nodes as hints)? >> >> Thanks, >> Leo >> >> _______________________________________________ >> riak-users mailing list >> riak-users@lists.basho.com >> http://lists.basho.com/mailman/listinfo/riak-users_lists.basho.com >> >> _______________________________________________ riak-users mailing list riak-users@lists.basho.com http://lists.basho.com/mailman/listinfo/riak-users_lists.basho.com
