When remove huge data, write and read file become very slow.

[skyjally]

Dear Developer:
Recently, I used Lizardfs for our data storage server to handle tens of millions pictures. When chunk server start to remove data, write file and read file become very slow.
Liardfs version: 3.12.0
meta and chunk server in the sample machine:
cpu:Intel(R) Xeon(R) Silver 4116 CPU @ 2.10GHz
mem:256G
meta and chunk use the default config.
I tried to change CHUNKS_SOFT_DEL_LIMIT and CHUNKS_HARD_DEL_LIMIT, it seems not improve write and read performance.
Here are the Lizardfs status:

   Is there any suggestion to handle this situation?

   Best regards!