[
https://issues.apache.org/jira/browse/CASSANDRA-8329?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14220914#comment-14220914
]
Alan Boudreault edited comment on CASSANDRA-8329 at 11/21/14 2:46 PM:
----------------------------------------------------------------------
Devs, here my test results.
h4. Test
* 12 disks of 2G of size
* Cassandra use default values for concurrent_compactors and
compaction_throughput_mb_per_sec.
* Goal: Stress the server with many concurent writes for 45-50 minutes.
h5. Results - No Patch
We can see the peak the LCS compaction of big sstables.
[^test_no_patch_2.0.jpg]
h5. Results - With Patch
Success. There is no more peak during the compaction.
[^test_with_patch_2.0.jpg]
Let me know if I can do anything else.
was (Author: aboudreault):
Devs, here my test results.
h4. Test
* 12 disks of 2G of size
* Cassandra use default values for concurrent_compactors and
compaction_throughput_mb_per_sec.
* Goal: Stress the server with many concurent writes for 45-50 minutes.
h5. Results - No Patch
We can see the peak the LCS compaction of big sstables.
!test_no_patch_2.0.jpg!
h5. Results - With Patch
Success. There is no more peak during the compaction.
[^test_with_patch_2.0.jpg]
Let me know if I can do anything else.
> LeveledCompactionStrategy should split large files across data directories
> when compacting
> ------------------------------------------------------------------------------------------
>
> Key: CASSANDRA-8329
> URL: https://issues.apache.org/jira/browse/CASSANDRA-8329
> Project: Cassandra
> Issue Type: Improvement
> Components: Core
> Reporter: J.B. Langston
> Assignee: Marcus Eriksson
> Fix For: 2.0.12
>
> Attachments:
> 0001-get-new-sstable-directory-for-every-new-file-during-.patch,
> test_no_patch_2.0.jpg, test_with_patch_2.0.jpg
>
>
> Because we fall back to STCS for L0 when LCS gets behind, the sstables in L0
> can get quite large during sustained periods of heavy writes. This can
> result in large imbalances between data volumes when using JBOD support.
> Eventually these large files get broken up as L0 sstables are moved up into
> higher levels; however, because LCS only chooses a single volume on which to
> write all of the sstables created during a single compaction, the imbalance
> is persisted.
--
This message was sent by Atlassian JIRA
(v6.3.4#6332)
