rsync performance weirdness

[Roland @web.de]

hi,

i observe some weirdness in rsync file transfer i cannot explain.

i'm transferring data from 2 freenas storages to a linux vm with zfsonlinux.

"fnask" is older freenas with rsync 3.1.1 running in daemon mode,
freenas-bnkw is more recent with rsync 3.1.2, also daemon-mode.

on the linux vm where the data is being pulled from the 2 freenas boxes,
i look onto io bandwidth being used with "iotop -a".

transfer from freenas-bnkw storage is much much slower then from fnask
storage.

why can i see two rsync processes transferring data from "fnask" but i
see only one rsync process with "freenas-bnkw" where the parent process
is transferring nothing ?

is there a difference in how this is being handled between 3.1.1 and
3.1.2 on the remote side ?

is this the reason for the slowness ?

regards
roland


Total DISK READ :     278.72 M/s | Total DISK WRITE :       0.00 B/s
Actual DISK READ:      97.09 M/s | Actual DISK WRITE:       0.00 B/s
   TID  PRIO  USER    DISK READ>  DISK WRITE  SWAPIN      IO COMMAND
32497 be/4 root        261.41 G      0.00 B  0.00 % 12.87 % rsync -av
--inplace fnask::backupall_S2V2_xen-sr-rpkn01-nfs/ .
32498 be/4 root        200.56 G     12.88 G  0.00 % 21.41 % rsync -av
--inplace fnask::backupall_S2V2_xen-sr-rpkn01-nfs/ .
24005 be/4 root         81.52 G     12.34 G  0.00 % 46.80 % rsync -av
--inplace freenas-bnkw::backupall_zfspool_sas_seagate/sr_rpkn02/ .
  3599 be/0 root         10.93 G      0.00 B  0.00 %  0.00 % [z_rd_int]
  3604 be/0 root         10.84 G      0.00 B  0.00 %  0.00 % [z_rd_int]
  3605 be/0 root         10.81 G      0.00 B  0.00 %  0.00 % [z_rd_int]


   ├─screen,14590
   │   └─bash,14591
   │       └─rsync,32497 -av --inplace
fnask::backupall_S2V2_xen-sr-rpkn01-nfs/ .
   │           └─rsync,32498 -av --inplace
fnask::backupall_S2V2_xen-sr-rpkn01-nfs/ .
   ├─screen,32261
   │   └─bash,32262
   │       └─rsync,24004 -av --inplace
freenas-bnkw::backupall_zfspool_sas_seagate/sr_rpkn02/ .
   │           └─rsync,24005 -av --inplace
freenas-bnkw::backupall_zfspool_sas_seagate/sr_rpkn02/ .