On 2020-09-15 02:09, Nathan Fish wrote:
What about hardlinks, are there any of those? Are
there lots of
directories or tiny (<4k) files?
The default allocation size of bluestore depends on the disk type. We
have this in our config:
# 4096 B instead of 16K (SSD) / 64K (HDD) to avoid large overhead for #
small (cephfs) files
bluestore_min_alloc_size_ssd = 4096
bluestore_min_alloc_size_hdd = 4096
If you have a lot of small files they will consume way more space on
CephFS with the default alloc size for realeases older than Octopus and
or using hdd drives.
The bad news: you cannot change that after the fact. You have to
reprovision your OSDs with a smaller alloc size if you want to change
that. On the upside: you can use default Ceph recovery mechanism to do
that without downtime.
Also, size=2 is not very safe. You want size=3,
min_size=2 if you are
doing replication.
^^ This, really!
Gr. Stefan