On Thu, 17 Oct 2019 at 06:22, Lars Marowsky-Bree <lmb@suse.com> wrote:
On 2019-10-16T11:28:25, " Honggang(Joseph) Yang " <eagle.rtlinux@gmail.com> wrote:
I'm glad to see more performance work and caching happening in Ceph!
I admit calling this a "tier" (to get the bike shedding done first ;-) is confusing me, because that used to mean something different. This seems to me to be more of a BlueStore feature based on hints/access from the upper layers?
User can explicitly send hint op or the do_op/agent send hint op based on object access statistics to trigger a migration.
So perhaps, at that level, it'd make sense to instead use the space on the RocksDB partition/device for this caching operation, instead of yet an additional device? (Intuitively, that's what most users already expect it does, anyway.)
yes, this is user friendly.
How would this, compared to bcache, possibly handle situations where multiple OSDs share one caching device?
SSD is split into multiple partitions. Each partition is assigned to an osd as fast partitions.
And does this only promote the local shard/replica? I'm wondering how this would affect EC pools.
yes, only promote the local shard/replica. But there is still some work to do to support ec pool.
Regards, Lars
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