[Gluster-devel] Trouble with write-back xlator

[Trung Le Thanh]

Hi all,

I have a glusterfs setup with 4 servers connected by a
100Mbps switch. The configuration files are exactly
like those on wiki. And I experienced a very strange
issue.

With write-back is enabled, the speed of copying file
from local hdd on a client to glusterfs is much slower
when write-back is disabled. I tried with many
different values of aggregate size (4KB -> 2MB) and
the result is still the same. I think that the
write-back is supposed to boost performance
dramatically in this case.

One more issue is when there is: when I copy a
directory to glusterfs, the speed is around 1.5MB/s.
When I start to copy another similar directory to
glusterfs, the speed drops to less than 1MB/s. I
supposed to saw the speed of 3MB/s.


Currently I have the content of /etc/sysctl.conf like
this:

net.core.somaxconn = 1024
net.core.netdev_max_backlog = 2500
net.ipv4.tcp_max_syn_backlog = 1024
net.ipv4.tcp_congestion_control = bic
net.ipv4.ip_local_port_range = 1024 65000
fs.file_max = 64000
net.ipv4.tcp_keepalive_time = 3600
net.ipv4.tcp_tw_reuse = 1
net.ipv4.tcp_tw_recycle = 1
net.ipv4.tcp_rfc1337 = 1
net.ipv4.tcp_no_metrics_save = 1
net.ipv4.tcp_timestamps = 0
net.ipv4.tcp_fin_timeout = 30

net.core.rmem_max = 16777216
net.core.wmem_max = 16777216
net.ipv4.tcp_rmem = 4096 87380 16777216
net.ipv4.tcp_wmem = 4096 65536 16777216

net.ipv4.conf.default.rp_filter = 1
net.ipv4.tcp_syncookies = 1
net.ipv4.tcp_synack_retries = 3
net.ipv4.tcp_syn_retries = 3


I don't know where the problem is and I really
appreciate any help from you

Thank you very much
Best regards,
Trung