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On Fri, 5 Jan 2001, Julian Anastasov wrote:
> I'm looking in my stats for the banner servers that serve only
> static images, LVS/DR. Wow, I have the stats in packets/sec and not in
> bytes/sec. Can you believe, the input packets are 90% of the output
> packets.
.
.
> So, it seems all my real servers have equal number for in
> and out packets. If I have 32 real servers for each 32 packets
> I will send only one output packet in WIN2K/NLB mode. Oh, yes, there
> are full-duplex links too.
>
> Guys, what show your stats for the incoming and outgoing
> packets in your real servers?
In my performance testing
http://www.linuxvirtualserver.org/Joseph.Mack/performance/single_realserver_performance.html
I found
1. that the maximum rate of packet throughput is independant of the packet
size (this is a tcpip problem, not an lvs problem). Thus if only 150 byte
packets are being passed instead of the mtu of 1500 bytes, then 100Mbps
ethernet will be limited to a throughput of 10Mbps.
2. I expect all packets need to be ACK'ed.
Thus the expected assymetry with LVS-DR of ftp downloads (where large
packets, ie mtu size, are being sent from the real-server to the client,
while the client is only sending ACK's), does not get us anything. The
packets are 1:1 inbound and outbound. In the outbound direction, a 100Mbps
link will be carrying 50% mtu sized packets (giving 50Mbs), while the
inbound throughput, having the same number of packets, will only have a
small amount of payload (say 1Mbps). The link will then be saturated at
51Mbps.
Joe
--
Joseph Mack mack@xxxxxxxxxxx
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