Hi!
I've confirmed that the write IO to the metadata pool is coming form active MDSes.
I'm experiencing very poor write performance on clients and I would like to see if there's anything I can do to optimise the performance.
Right now, I'm specifically focussing on speeding up this use case:
In CephFS mounted dir:
$ time unzip -q wordpress-seo.12.9.1.zip
real 0m47.596s user 0m0.218s sys 0m0.157s
On RBD mount:
$ time unzip -q wordpress-seo.12.9.1.zip
real 0m0.176s user 0m0.131s sys 0m0.045s
The difference is just too big. I'm having real trouble finding a good reference to check my setup for bad configuration etc.
I have network bandwidth, RAM and CPU to spare, but I'm unsure on how to put it to work to help my case.
Are there a lot of directories to be created from that zip file? I think it boils down to the directory operations that need to be performed synchrously. See https://fosdem.org/2020/schedule/event/sds_ceph_async_directory_ops/ https://fosdem.org/2020/schedule/event/sds_ceph_async_directory_ops/attachme... https://video.fosdem.org/2020/H.1308/sds_ceph_async_directory_ops.webm Gr. Stefan -- | BIT BV https://www.bit.nl/ Kamer van Koophandel 09090351 | GPG: 0xD14839C6 +31 318 648 688 / info@bit.nl