[Bugs] [Bug 1691833] New: Client sends 128KByte network packet for 0 length file copy
bugzilla at redhat.com
bugzilla at redhat.com
Fri Mar 22 15:57:15 UTC 2019
https://bugzilla.redhat.com/show_bug.cgi?id=1691833
Bug ID: 1691833
Summary: Client sends 128KByte network packet for 0 length file
copy
Product: GlusterFS
Version: 5
Hardware: x86_64
OS: Linux
Status: NEW
Component: core
Severity: medium
Assignee: bugs at gluster.org
Reporter: otto.jonyer at gmail.com
CC: bugs at gluster.org
Target Milestone: ---
Classification: Community
Created attachment 1546951
--> https://bugzilla.redhat.com/attachment.cgi?id=1546951&action=edit
Wireshark report of the network overhead
Description of problem:
Installed Ubuntu Server 18.10 from official release.
Installed debian packages from ppa:gluster/glusterfs-5 (download.gluster.org)
The problem was originally reproduced on CentOs based on with custom
compilation of glusterfs-5.1
Created the simplest replica filesystem on 2 nodes and mounted on one of the
nodes but it is also reproducible when mounted from dedicated client as well.
Created a 0 length file with "touch /tmp/0length"
Copied the file to gluster mount.
Network capture shows that 128KByte packet is sent to both replica which is a
huge network overhead for really small files.
the commands I've used:
mkdir /mnt/brick
gluster peer probe 192.168.56.100
gluster volume create gv0 replica 2 192.168.56.100:/mnt/brick
192.168.56.101:/mnt/brick force
gluster volume start gv0
mkdir /mnt/gv0
mount -t glusterfs 192.168.56.100:/gv0 /mnt/gv0
touch /tmp/0length
cp /tmp/0length /mnt/gv0
Version-Release number of selected component (if applicable):
5.5-ubuntu1~cosmic1: glusterfs-client glusterfs-common glusterfs-server
How reproducible:
Steps to Reproduce:
1) on both nodes: mkdir /mnt/brick
2) on 192.168.56.101: gluster peer probe 192.168.56.100
3) gluster volume create gv0 replica 2 192.168.56.100:/mnt/brick
192.168.56.101:/mnt/brick force
4) gluster volume start gv0
5) mkdir /mnt/gv0
6) mount -t glusterfs 192.168.56.100:/gv0 /mnt/gv0
7) touch /tmp/0length
8) tcpdump -s 0 -w /tmp/glusterfs.pkt 'host 192.168.56.100'
9) cp /tmp/0length /mnt/gv0
10) stop network capture and load into wireshark
Actual results:
The network capture is 256KByte length and I see 1-1 'proc-27' calls to both
glusterfs nodes with 128KB sizes.
Expected results:
The network capture is a few kilobytes and low network overhead for small
files.
Additional info:
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