After a long vdbench test, the performance is in the single digits

[YunhuiChen]

Describe the bug (描述bug)

To Reproduce (复现方法)
data_errors=1
fsd=fsd1,anchor=/home/nbs/failover/test9,depth=1,width=10,files=10,sizes=1000m,shared=yes,openflags=o_direct
fsd=fsd2,anchor=/home/nbs/failover/test2,depth=1,width=10,files=10,sizes=(200m,0),shared=yes,openflags=o_direct
fsd=fsd3,anchor=/home/nbs/failover/test3,depth=1,width=10,files=100,sizes=(1m,0),shared=yes,openflags=o_direct
fsd=fsd4,anchor=/home/nbs/failover/test4,depth=1,width=10,files=10,sizes=(1000m,0),shared=yes,openflags=o_direct
fsd=fsd5,anchor=/home/nbs/failover/test5,depth=1,width=10,files=10,sizes=(100m,0),shared=yes,openflags=o_direct
fsd=fsd6,anchor=/home/nbs/failover/test6,depth=1,width=10,files=10,sizes=(100m,0),shared=yes,openflags=o_direct
fsd=fsd7,anchor=/home/nbs/failover/test7,depth=1,width=10,files=10,sizes=(10m,0),shared=yes,openflags=o_direct
fwd=fwd1,fsd=fsd*,threads=10,xfersize=(512,20,4k,20,64k,20,512k,20,1024k,20),fileio=random,fileselect=random,rdpct=50
rd=rd1,fwd=fwd*,fwdrate=max,format=restart,elapsed=120000,interval=1

Expected behavior (期望行为)

Versions (各种版本)
OS:
Compiler:
curve-mds:
curve-chunkserver:
curve-snapshotcloneserver:
curve-sdk:
nebd:
curve-nbd:

Additional context/screenshots (更多上下文/截图)