Bug #42345
closedOSD: When object compression ratio is high(but less than “bluestore_compression_required_ratio”), compression did not work
0%
Description
Version: nautilus
I set value “.98” to “bluestore_compression_required_ratio”. Then put some objects into the cluster by rbd. The compress-type is zlib, and the object’s compression-rate is 93% more or less.But compression did not work.
I observed “ceph daemon osd.0 perf dump | grep bluestore”, and the relevant value didn’t change. Then I wrote some log to the source code and rebuild the Ceph projects.The log-print showed that the soft flow didn’t enter compression-path.
Updated by Fengzhe Han over 4 years ago
Fengzhe Han wrote:
Version: nautilus
I set value “.98” to “bluestore_compression_required_ratio”. Then put some objects into the cluster by rbd. The compress-type is zlib, and the object’s compression-rate is 93% more or less.But compression did not work.
I observed “ceph daemon osd.0 perf dump | grep bluestore”, and the relevant value didn’t change. Then I wrote some log to the source code and rebuild the Ceph projects.The log-print showed that the soft flow didn’t enter compression-path.
The parameters which I set :
bluestore_compression_algorithm = zlib
bluestore_compression_mode = force
bluestore_compression_required_ratio = .98
Updated by Vikhyat Umrao over 4 years ago
- Project changed from RADOS to bluestore
Updated by Igor Fedotov over 4 years ago
- Status changed from New to Need More Info
would you please set debug bluestore to 20, repeat the test and share the log? Thanks!
Updated by Igor Fedotov over 4 years ago
also please note that compression makes sense for writes that are at least 2x times as large as bluestore_min_alloc_size (16K/64K for SSD/HDD respectively). Smaller writes don't pass via compression path.
Updated by Kefu Chai over 4 years ago
Updated by Josh Durgin over 4 years ago
- Status changed from Need More Info to Closed
Sounds like there wasn't a bug here, just some confusion about config meaning.