[THIN] Re: Citrix Server with 2 Nics
- From: Rob Slayden <rslayden@xxxxxxxxxxxxx>
- To: "'thin@xxxxxxxxxxxxx'" <thin@xxxxxxxxxxxxx>
- Date: Sun, 7 Sep 2003 18:49:29 -0700
Actually, the point I was trying to make was that in our environment
(150-180 users connecting per server), the bandwidth metrics that were used
to support the migration FROM Cisco Fast Etherchannel teams TO Fault
Tolerant teams were misleading. Admittedly, there may be a registry hack or
a TCP/IP stack configuration parameter that would enable a greater number of
session initializations per server per team, but I did not delve into that
aspect of this issue as we had a farm that was functioning very well with
FEC teams and then it fell apart with fault tolerant teams. The changed
configuration "worked," but we injected many apparent "latency-type" issues
into the farm that affected server-to-server and server-to-cluster
communications. We do intend to investigate the potential of running
multiple FEC teams on each server (2 per server), but that requires a
greater port density (twice as many switch ports as we currently use).
Has anyone tested 2 Cisco FEC teams on a single server to 2 different
switches? I guess the moral of the story for me was that there may be
additional benefits beyond bandwidth within a teamed-NIC configuration that
affect the optimal performance of a MetaFrame server farm. The ironic part
is that the impetus for the infrastructure modification was to enable the
Networking group to take a switch down for maintenance without affecting
application access, but the implementation of this design change did
adversely affect both the user experience and proper operation of the farm.
Unfortunately, it also affected the short-term credibility of the Networking
group's infrastructure design capability.
rob
-----Original Message-----
From: Dave Nelson [mailto:David.Nelson@xxxxxxxxxxxxxxxxxxx]
Sent: Saturday, September 06, 2003 3:04 PM
To: thin@xxxxxxxxxxxxx
Subject: [THIN] Re: Citrix Server with 2 Nics
That's really strange... I have 4 6513 core switches and all of our servers
are Layer 2 redundant with one connection to one of the core switches and
the secondary connection to another of the core switches. We also have a
mish-mosh of various Compaq server types (580G1, 580G2, 380G1, 380G2, 380G3,
etc), but they're all configured to use SmartSwitch fault tolerance.
I will give you a word of advice here: we ran into issues when the virtual
MAC address used by the team is not the same as the Preferred Primary NIC.
We had very strange issues with network performance and mysterious failovers
on the NICs. Another piece of advise is to have your network folks look at
what rev of CatOS you're running on those 6513s. We just got done upgrading
to 7.6.3 which fixed a bunch of issues we were having with our 10/100/1000
copper blades, but introduced new issues with EARL, HSRP, and port security.
Depending on your configuration, your mileage will vary.
David J. Nelson, CCEA, CCNP, CCDP, MCNE, MCSE, MCDBA, SCE
Network Specialist II
City of Henderson
240 Water Street
Henderson, Nevada 89015
Tel: 702.565.3851
Fax: 702.566.2296
Cell: 702.373-2932
E-Mail: djn@xxxxxxxxxxxxxxxxxx <mailto:djn@xxxxxxxxxxxxxxxxxx>
Home Page: http://www.ci.henderson.nv.us <http://www.ci.henderson.nv.us>
>>> rslayden@xxxxxxxxxxxxx 09/05/2003 5:31:33 PM >>>
A little more info on the benefits of Compaq dual NIC configurations running
Cisco Fast Etherchannel. About 2 weeks ago our network engineer monitored
bandwidth utilization of the network traffic across our 27 MF 1.8 servers
and 4 clusters (Compaq PL 6400s/DL580s) and decided that the teamed NICs
would allow more effective fault tolerance if they were re-configured to be
fault-tolerant teams and the NICs split across two Cisco 6513 switches.
After making the changes, the performance in the farm went to heck in a
handbasket from the user perspective, including servers dropping off the MF
browse list, disconnected "black screen" sessions, Citrix servers
unavailable, and many profile and user home subdirectory issues. The 4
SAN-attached clusters that support the farm (profiles and user home subdirs)
had been 4-port Fast Etherchannel teams. Needless to say that after a week
of trying to convince the network guys that it was the NIC reconfiguration
(it's not the ne twork, it's CITRIX!), we finally rolled everything back and
lo and behold, no more issues!
I don't know how many are running dual NICs configured for Cisco Fast
Etherchannel in their MetaFrame environments but it definitely provides a
significant performance benefit in our environment despite the misleading
bandwidth utilization metrics.
BTW, auto configuration is NEVER a good idea for media settings when switch
attached! I've seen lots of strange "network" problems occur when we have
neglected to hard code speed/duplex on server NIC ports.
HTH,
Rob Slayden
24 Hour Fitness, Inc.
-----Original Message-----
From: Claus, Brian [mailto:BClaus@xxxxxxxxxxxxx
<mailto:BClaus@xxxxxxxxxxxxx> ]
Sent: Friday, September 05, 2003 1:35 PM
To: thin@xxxxxxxxxxxxx
Subject: [THIN] Re: Citrix Server with 2 Nics
Only problem is if the NIC teaming is set to 10\half and your switch is
set to 100\full...major performance problems...just do a ping servername
-t I've seen 1 ping then multiple timeouts, then a few pings, then more
timeouts, etc...
_____
Brian Claus, A+, Network+, MCP
Network Administrator
WESCO Distribution, Inc.
225 West Station Square Drive, Suite 700
Pittsburgh, PA 15219-1122
Phone: 412-454-2412
Fax: 412-454-2540
bclaus@xxxxxxxxxxxxx <mailto:bclaus@xxxxxxxxxxxxx
<mailto:bclaus@xxxxxxxxxxxxx> >
_____
-----Original Message-----
From: Jason Benway [mailto:benwayj@xxxxxxxx <mailto:benwayj@xxxxxxxx> ]
Sent: Friday, September 05, 2003 3:19 PM
To: 'thin@xxxxxxxxxxxxx'
Subject: [THIN] Citrix Server with 2 Nics
Any know problems having my Citrix XP servers have 2 nic on the same
subnet?
My new Dell Blade servers has dual nics for redundancy. Can/will this
cause
any problems?
Thanks,jb
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