Russian post is here
We are using Project Voldemort in our project. If you are also hit some disk space problems as we do -
1. Please check current utilization of files -
# java -jar /usr/local/voldemort/lib/je-4.0.92.jar DbSpace -h /usr/local/voldemort/data/bdb -u
File Size (KB) % Used
-------- --------- ------
00000000 61439 78
00000001 61439 75
00000002 61439 73
00000003 61439 74
...
000013f6 61415 1
000013fd 61392 2
000013fe 61411 3
00001400 61432 2
00001401 61439 1
...
0000186e 61413 100
0000186f 61376 100
00001870 16875 95
TOTALS 112583251 7
2. If TOTALS is much less than default (50%) - it seem that you have cache size shortage. Please calculate cache size for your number of records ( using your key and data average size, of course ) -
# java -jar /usr/local/voldemort/lib/je-4.0.92.jar DbCacheSize -records 1000000 -key 100 -data 300
Inputs: records=1000000 keySize=100 dataSize=300 nodeMax=128 density=80% overhead=10%
Cache Size Btree Size Description
-------------- -------------- -----------
177,752,177 159,976,960 Minimum, internal nodes only 208,665,600 187,799,040 Maximum, internal nodes only 586,641,066 527,976,960 Minimum, internal nodes and leaf nodes
617,554,488 555,799,040 Maximum, internal nodes and leaf nodes
Btree levels: 3
and adjust bdb.cleaner.threads accordingly (as maximum of internal nodes).
After this space must be reclaimed (after couple of hours or days - it depends of DB size).
Official and unofficial BDB JE documentation is very helpful.
Morale of the story - even underlying technology must be thoroughly investigated. :)
