Greetings all. My name is Jack and I work for an image hosting company Image Shack, we also have a property thats widely used as a twitter app called yfrog (yfrog.com).
Image-Shack gets close to two million image uploads per day, which are usually stored on regular servers (we have about 700), as regular files, and each server has its own host name, such as (img55). I've been researching on how to improve our backend design in terms of data safety and stumped onto the Hbase project. We have been running hadoop for data access log analysis for a while now, quite successfully. We are receiving about 2 billion hits per day and store all of that data into RCFiles (attribution to Facebook applies here), that are loadable into Hive (thanks to FB again). So we know how to manage HDFS, and run mapreduce jobs. Now, I think hbase is he most beautiful thing that happen to distributed DB world :). The idea is to store image files (about 400Kb on average into HBASE). The setup will include the following configuration: 50 servers total (2 datacenters), with 8 GB RAM, dual core cpu, 6 x 2TB disks each. 3 to 5 Zookeepers 2 Masters (in a datacenter each) 10 to 20 Stargate REST instances (one per server, hash loadbalanced) 40 to 50 RegionServers (will probably keep masters separate on dedicated boxes). 2 Namenode servers (one backup, highly available, will do fsimage and edits snapshots also) So far I got about 13 servers running, and doing about 20 insertions / second (file size ranging from few KB to 2-3MB, ave. 400KB). via Stargate API. Our frontend servers receive files, and I just fork-insert them into stargate via http (curl). The inserts are humming along nicely, without any noticeable load on regionservers, so far inserted about 2 TB worth of images. I have adjusted the region file size to be 512MB, and table block size to about 400KB , trying to match average access block to limit HDFS trips. So far the read performance was more than adequate, and of course write performance is nowhere near capacity. So right now, all newly uploaded images go to HBASE. But we do plan to insert about 170 Million images (about 100 days worth), which is only about 64 TB, or 10% of planned cluster size of 600TB. The end goal is to have a storage system that creates data safety, e.g. system may go down but data can not be lost. Our Front-End servers will continue to serve images from their own file system (we are serving about 16 Gbits at peak), however should we need to bring any of those down for maintenance, we will redirect all traffic to Hbase (should be no more than few hundred Mbps), while the front end server is repaired (for example having its disk replaced), after the repairs, we quickly repopulate it with missing files, while serving the missing remaining off Hbase. All in all should be very interesting project, and I am hoping not to run into any snags, however, should that happens, I am pleased to know that such a great and vibrant tech group exists that supports and uses HBASE :). -Jack
