common/options: enable multiple rocksdb compaction threads for filestore #18232
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One of the major benefits of rocksdb over leveldb is multithreaded compaction. The default of 1 thread does not provide much benefit, and is insufficient for heavy rgw workloads. For high-write and delete omap workloads I've seen up to 8 compaction threads be used. There's little overhead to having a higher max than are needed, so set the default to 8. Signed-off-by: Josh Durgin <jdurgin@redhat.com>
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luminous backport: #18234 |
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jewel backport included in #18010 |
tchaikov
reviewed
Oct 11, 2017
| @@ -3673,7 +3673,7 @@ std::vector<Option> get_global_options() { | |||
| // filestore | |||
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| Option("filestore_rocksdb_options", Option::TYPE_STR, Option::LEVEL_DEV) | |||
| .set_default("compaction_readahead_size=2097152") | |||
| .set_default("max_background_compactions=8;compaction_readahead_size=2097152") | |||
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nit, can we use , as the separator? to be consistent with other _rocksdb_options.
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even though, "max_background_compactions" is still supported, but since rocksdb 5.6.0, max_background_compactions is replaced with max_background_jobs. to have 8 background compactions, we can specify "max_background_jobs=10", in which, 2 jobs will be allocated for "max_background_flushes".
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okay, it's more backport-friendly. we can update it in master after it gets merged.
tchaikov
approved these changes
Oct 18, 2017
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One of the major benefits of rocksdb over leveldb is multithreaded
compaction. The default of 1 thread does not provide much benefit, and
is insufficient for heavy rgw workloads.
For high-write and delete omap workloads I've seen up to 8 compaction
threads be used. There's little overhead to having a higher max than
are needed, so set the default to 8.
Signed-off-by: Josh Durgin jdurgin@redhat.com