Re: packet dropping on solaris

["Jonathan Khoo" <khoohuit () gmail com>]

Hi Michele,

Thanks for your advice. Solaris uses ndd, something like sysctl for
linux. I tried with tethereal and also experience packet dropping and
all I did was to transfer a 10mb file from a linux box to a solaris
box.

I had played around with the following kernel parameters, but things
did not improve.

tcp_max_buf
tcp_recv_hiwat
tcp_recv_hiwat_minmss

http://developers.sun.com/solaris/articles/streams_bandwith.html

According to the above link, I can use SBIOCSCHUNK to change the
stream high and low watermark. That is already handled inside the
libpcap code (pcap-dlpi.c). The article also mentioned about the use
of SB_NO_DROPS. However, I read from the tcpdump archives that this
was used previously and it caused packet drops.

Hmm...Does anyone has any advice on how I can proceed ? Did I miss out
anything important?

Thanks in advance for any advices!

cheers,
jonathan


On 5/26/06, Michele Sciuto <m.sciuto () dist unige it> wrote:
> Hello Jonathan,
> we are working at the same topic on a Linux Debian system.
>
> I suggest that you adjust the following kernel parameters in order to
> improve the number of packets captured (I don't know the equivalence in
> Solaris...).
>
> /proc/sys/net/core/rmem_default     409715100 bytes
> /proc/sys/net/core/rmem_max    409715100 bytes
> /proc/sys/net/core/netdev_max_backlog    300000 pkts
>
> If you have a dual-cpu server, you can get improvements recompiling
> the kernel with the SMP support.
>
> In our system the bottleneck is the write-to-disk process, so you can
> verify the trouble acquiring the traffic without writing to disk (-w
> /dev/null); check the disk speed too (the command in Linux is hdparm).
>
> Do you have drops both by tcpdump and by the nic?
>
> Bye, michele

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