On 5/13/20 12:43 AM, RafaĹ? WÄ?doĹ?owski wrote:
Hi,
I noticed strange situation in one of our clusters. The OSD deamons are taking too much RAM.
We are running 12.2.12 and have default configuration of osd_memory_target (4GiB).
Heap dump shows:
osd.2969 dumping heap profile now.
------------------------------------------------
MALLOC: 6381526944 ( 6085.9 MiB) Bytes in use by application
MALLOC: + 0 ( 0.0 MiB) Bytes in page heap freelist
MALLOC: + 173373288 ( 165.3 MiB) Bytes in central cache freelist
MALLOC: + 17163520 ( 16.4 MiB) Bytes in transfer cache freelist
MALLOC: + 95339512 ( 90.9 MiB) Bytes in thread cache freelists
MALLOC: + 28995744 ( 27.7 MiB) Bytes in malloc metadata
MALLOC: ------------
MALLOC: = 6696399008 ( 6386.2 MiB) Actual memory used (physical + swap)
MALLOC: + 218267648 ( 208.2 MiB) Bytes released to OS (aka unmapped)
MALLOC: ------------
MALLOC: = 6914666656 ( 6594.3 MiB) Virtual address space used
MALLOC:
MALLOC: 408276 Spans in use
MALLOC: 75 Thread heaps in use
MALLOC: 8192 Tcmalloc page size
------------------------------------------------
Call ReleaseFreeMemory() to release freelist memory to the OS (via madvise()).
Bytes released to the OS take up virtual address space but no physical memory.
IMO "Bytes in use by application" should be less than osd_memory_target. Am I correct?
I checked heap dump with google-pprof and got following results.
Total: 149.4 MB
60.5 40.5% 40.5% 60.5 40.5% rocksdb::UncompressBlockContentsForCompressionType
34.2 22.9% 63.4% 34.2 22.9% ceph::buffer::create_aligned_in_mempool
11.9 7.9% 71.3% 12.1 8.1% std::_Rb_tree::_M_emplace_hint_unique
10.7 7.1% 78.5% 71.2 47.7% rocksdb::ReadBlockContents
Does it mean that most of RAM is used by rocksdb?
It looks like your heap dump is only accounting for 149.4MB of the
memory so probably not representative across the whole ~6.5G. Instead
could you try dumping the mempools via "ceph daemon osd.2969 dump_mempools"?
How can I take a deeper look into memory usage ?
Beyond looking at the mempools, you can see the bluestore cache
allocation information by either enabling debug bluestore and debug
priority_cache_manager 5, or potentially looking at the PCM perf
counters (I'm not sure if those were in 14.2.12 though). Between the
heap data, mempool data, and priority cache records, it should become
clearer what's going on.
Mark
Regards,
RafaĹ? WÄ?doĹ?owski
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