[Gluster-devel] Trouble with write-back xlator

Anand Avati avati at zresearch.com
Wed Jul 18 11:13:34 UTC 2007


Trung,
  sorry for the delayed response. Please add the option 'option flush-behind
off' to write-behind section and try, that shoud help for very small files.

thanks,
avati

2007/6/13, Trung Le Thanh <trung_bmt at yahoo.com>:
>
> 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
>
>
>
>
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>



-- 
Anand V. Avati



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