[
https://issues.apache.org/jira/browse/CASSANDRA-9747?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15083761#comment-15083761
]
Robert Stupp commented on CASSANDRA-9747:
-----------------------------------------
[~RomanB] can you elaborate a bit more on how you come to the conclusion that
JNA has a direct influence to disk I/O performance?
> JNA makes Cassandra slower
> --------------------------
>
> Key: CASSANDRA-9747
> URL: https://issues.apache.org/jira/browse/CASSANDRA-9747
> Project: Cassandra
> Issue Type: Bug
> Environment: Cassandra 2.0.14; JNA 4.x; 32-core CPU; 64GB RAM (8GB
> heap); 2 physical HDDs used as commit and data; Java 1.7
> Reporter: Roman Bielik
> Priority: Minor
>
> When JNA is loaded (as recommended in the production settings), it has
> negative effect on performance, especially when used with HDD => it
> significantly increases the disk IO wait.
> It looks like JNA works fine only when used in combination with SSD disk.
> Otherwise it is better not to use JNA at all. This is very unexpected
> behavior, can you please analyse?
> Test description:
> Roughly 50% reads and 50% writes of about 1.5kB records using Thrift
> interface.
> Test results (sorted by performance):
> *HDD + JNA*
> Worst performance. High IO wait.
> *HDD, no JNA*
> Good performance. Low IO wait, but the Cassandra CPU usage is quite high.
> *SSD + JNA*
> Seems to provide the best performance. Low IO wait. Low Cassandra CPU usage.
--
This message was sent by Atlassian JIRA
(v6.3.4#6332)
