Eric, all this info would be great as a FAQ on the website. :) -- Christopher L Tubbs II http://gravatar.com/ctubbsii
On Wed, Jul 24, 2013 at 8:35 AM, Eric Newton <[email protected]> wrote: > Assuming that 5 billion records means 5 billion Key/Values, this is nearly > 100K K-V/sec/node, which isn't so bad. If the key/values are small and > uniformly distributed, 200K is closer to the rate you can expect given > decent drives. > > If you are only concerned with ingest, crank up the size of the in-memory > map and increase the compaction ratio from 3 to 5 (or even as high as 10). > This will reduce the number of re-writes of your data. If you don't care > about possible data loss, turn off the write-ahead log on your table, or > reduce the replication factor for the write-ahead log. > > Make sure your table is pre-split, if possible, to maximize parallel > performance during initial ingest. Aim for 10-50 tablets per server. > > If the latency of waiting for the data to be prepped does not bother you, it > is almost always more efficient to use bulk ingest. Can you wait 30 > minutes to queue up enough data, and then another 5-15 for the map/reduce > job to produce the RFiles? > > There's a fair amount of overhead to starting a mapper. You may want to > experiment with larger map jobs. > > -Eric > > > On Wed, Jul 24, 2013 at 2:26 AM, Dickson, Matt MR > <[email protected]> wrote: >> >> UNCLASSIFIED >> >> Hi, >> >> I'm trying to improve ingest performance on a 12 node test cluster. >> Currently I'm loading 5 billion records in approximately 70 minutes which >> seems excessive. Monitoring the job there are 2600 map jobs (there is no >> reduce stage, just the mapper) with 288 running at any one time. The >> performance seems slowest in the early stages of the job prior to to min or >> maj compactions occuring. Each server has 48 GB memory and currently the >> accumulo settings are based on the 3GB settings in the example config >> directory, ie tserver.memory.maps.max = 1GB, tserver.cache.index.site=50M >> and tserver.cache.index.site=512M. All other settings on the table are >> default. >> >> Questions. >> >> 1. What is Accumulo doing in the initial stage of a load and which >> configurations should I focus on to improve this? >> 2. At what ingest rate should I consider using the bulk ingest process >> with rfiles? >> >> Thanks >> Matt >> >> IMPORTANT: This email remains the property of the Department of Defence >> and is subject to the jurisdiction of section 70 of the Crimes Act 1914. If >> you have received this email in error, you are requested to contact the >> sender and delete the email. > >
