If anybody has 5 minutes could they just clarify a couple of things for me
1. onode count, should this be equal to the number of objects stored on the OSD?
Through reading several posts, there seems to be a general indication that this
is the case, but looking at my OSD's the maths don't
work.
Eg.
ceph osd df
ID CLASS WEIGHT REWEIGHT SIZE USE AVAIL %USE VAR PGS
0 hdd 2.73679 1.00000 2802G 1347G 1454G 48.09 0.69 115
So 3TB OSD, roughly half full. This is pure RBD workload (no snapshots or
anything clever) so let's assume worse case scenario of
4MB objects (Compression is on however, which would only mean more objects for
given size)
1347000/4=~336750 expected objects
sudo ceph daemon osd.0 perf dump | grep blue
"bluefs": {
"bluestore": {
"bluestore_allocated": 1437813964800,
"bluestore_stored": 2326118994003,
"bluestore_compressed": 445228558486,
"bluestore_compressed_allocated": 547649159168,
"bluestore_compressed_original": 1437773843456,
"bluestore_onodes": 99022,
"bluestore_onode_hits": 18151499,
"bluestore_onode_misses": 4539604,
"bluestore_onode_shard_hits": 10596780,
"bluestore_onode_shard_misses": 4632238,
"bluestore_extents": 896365,
"bluestore_blobs": 861495,
99022 onodes, anyone care to enlighten me?
2. block.db Size
sudo ceph daemon osd.0 perf dump | grep db
"db_total_bytes": 8587829248,
"db_used_bytes": 2375024640,
2.3GB=0.17% of data size. This seems a lot lower than the 1% recommendation
(10GB for every 1TB) or 4% given in the official docs. I
know that different workloads will have differing overheads and potentially
smaller objects. But am I understanding these figures
correctly as they seem dramatically lower?
Regards,
Nick
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