diff --git a/docs/VOLUME.md b/docs/VOLUME.md index 151d5f8..8510161 100644 --- a/docs/VOLUME.md +++ b/docs/VOLUME.md @@ -56,9 +56,17 @@ On the flip side, it could be argued that the 73% difference under-estimates the ## Riak Cluster Test - 2 -to be completed .. +An identical test was run as above, but with d2.2xlarge instances, so that performance on spinning disks could be tested for comparison. This however tanked with sync_on_write enabled regardless if this was tested with leveled or leveldb - with just 1,000 transactions per second supported. -As above but on d2.2xlarge EC2 nodes for HDD comparison +Although append_only writes are being used, almost every write still requires a disk head movement even if the server had all reads handled by in-memory cache (as there are normally more vnodes on the server than there are disk heads). It is clear that without a Flash-Backed Write Cache, spinning disks are unusable as the sole storage mechanism. + +Also tested was d2.2zlarge clusters, but without sync_on_write. Results were: + +leveled Results | eleveldb Results +:-------------------------:|:-------------------------: +![](../test/volume/cluster_two/output/summary_nosync_d2_leveled.png "LevelEd") | ![](../test/volume/cluster_two/output/summary_nosync_d2_leveldb.png "LevelDB") + +This test showed a 26.7% improvement in throughput when using LevelEd. The improvement in tail latency in this test had leveled at about 25% of the tail latency of leveldb. ## Riak Cluster Test - 3 diff --git a/test/volume/cluster_two/output/summary_nosync_d2_leveldb.png b/test/volume/cluster_two/output/summary_nosync_d2_leveldb.png new file mode 100644 index 0000000..c5db567 Binary files /dev/null and b/test/volume/cluster_two/output/summary_nosync_d2_leveldb.png differ diff --git a/test/volume/cluster_two/output/summary_nosync_d2_leveled.png b/test/volume/cluster_two/output/summary_nosync_d2_leveled.png new file mode 100644 index 0000000..0a75ad7 Binary files /dev/null and b/test/volume/cluster_two/output/summary_nosync_d2_leveled.png differ