[Samba] Performance Issues with GBit LAN

Tom Hibbert tom at nsp.co.nz
Tue Oct 12 21:18:18 GMT 2004

Hi Steffen
>At first: Thanks for the response.

>Here are the performance Measures of my Harddisks in the Server. As the
>Harddisks are not connected to the Onboard IDE, they're not limited to

>/dev/sdb is the RAID 0, Connected to the PCI Raid Controller Card. The
>Share Samba provides is on the RAID, so performance should be enough.

>Timing buffered disk reads:  64 MB in  1.55 seconds = 41.29 MB/sec

>(Redhat9.0, 256 SD-RAM, 300MHz PII, RTL8169 NIC, 2x Western Digital
WD200JB >RAID 0) to my Windows-PC(AMD Athlon XP 1800+, 1024 MB DDR-RAM,
WINXP PRO, >RTL8169 NIC, 2x Western Digital WD080JB RAID 0)

Looking at the configuration of the server PC, you have a Realtek
network card and an unspecified RAID card on a P2 300. I'm guessing that
the machine is based on an LX or BX chipset with PC66 or PC100 ram.
You have 66mhz bandwidth to play with in the PCI bus. You also have
66mhz FSB thanks to the PII 300 CPU. All the benchmarking you have done
(both Iperf and hdparm) both test the two subsystems individually, not
together. My initial guess is that your PCI bus and/or CPU cannot drive
this system at its full potential. Look at the load average on the
server during transfer.

Secondly you are running Redhat 9 with a Realtek 8169. There were a
number of issues with the stock Redhat 9 kernel versus a Realtek 8169,
see here
1&highlight=8169. In fact these users are reporting only 8-10mb
throughput which is exactly what you are describing.

My advice to you is to roll a custom kernel for your system (optimized
for Pentium 2, raid and network drivers built into kernel instead of
modules). Then perform a proper hard disk benchmark using Bonnie++ so
you know what the disks are truly capable of (hdparm -t doesn't cut it
in this respect).
Then I would compare the difference between throughput serving from both
your SCSI disk (sda) and RAID array with the benchmark data given by
bonnie++. This may reveal a CPU or FSB bottleneck.

Good luck and thanks


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