Re: jumbo frames?
On Mon, 2012-08-27 at 16:02 -0700, Todd And Margo Chester wrote: > On 08/27/2012 03:39 PM, Stephen John Smoogen wrote: > > On 27 August 2012 14:48, Todd And Margo Chester > > wrote: > >> Hi All, > >> > >> Can anyone tell me what this means? > >> > >> just disable jumbo frames on centos host interface > >> ifcfg and ethernet switch. > > > > Well first of all. What is giving you this error or message? Jumbo > > frames are not usually turned on CentOS/Scientific Linux without some > > extra configuration (eg in /etc/sysconfig/network-scripts/ifcfg-eth0 > > or the likes.). To see if they are enabled on the system.. ifconfig > > eth0 and look for the MTU line. If it is 1500 that is standard. If it > > is 9000 then it has been configured to be such somehow. > > > >> Many thanks, > >> -T > > > Oh, I am getting frequent BSODs when I shut down my > KVM virtual XP. Someone over on the centos vm list told > me he cured his by removing jumbo frames. I did not > know what he was talking about, so I asked over here. http://en.wikipedia.org/wiki/Jumbo_frame Steve
Re: jumbo frames?
On 08/27/2012 03:41 PM, jdow wrote:
On 2012/08/27 15:32, Todd And Margo Chester wrote:
On 08/27/2012 03:16 PM, jdow wrote:
ifconfig comes to mind.
{^_^}
$ ifconfig virbr0
virbr0Link encap:Ethernet HWaddr 52:54:00:EB:2D:7B
inet addr:192.168.122.1 Bcast:192.168.122.255
Mask:255.255.255.0
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:0 errors:0 dropped:0 overruns:0 frame:0
TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:0
RX bytes:0 (0.0 b) TX bytes:0 (0.0 b)
What am I looking for?
MTU:1500
This interface is not doing jumbo frames.
Betcha this shows the same thing:
cat /sys/class/net/virbr0/mtu
(Or find it under /sys/devices/virtual/net possibly.)
Mess with it carefully.
{^_^}
I would loose that bet:
$ cat /sys/class/net/virbr0/mtu
1500
Re: jumbo frames?
On 08/27/2012 03:39 PM, Stephen John Smoogen wrote: On 27 August 2012 14:48, Todd And Margo Chester wrote: Hi All, Can anyone tell me what this means? just disable jumbo frames on centos host interface ifcfg and ethernet switch. Well first of all. What is giving you this error or message? Jumbo frames are not usually turned on CentOS/Scientific Linux without some extra configuration (eg in /etc/sysconfig/network-scripts/ifcfg-eth0 or the likes.). To see if they are enabled on the system.. ifconfig eth0 and look for the MTU line. If it is 1500 that is standard. If it is 9000 then it has been configured to be such somehow. Many thanks, -T Oh, I am getting frequent BSODs when I shut down my KVM virtual XP. Someone over on the centos vm list told me he cured his by removing jumbo frames. I did not know what he was talking about, so I asked over here.
Re: jumbo frames?
On 2012/08/27 15:32, Todd And Margo Chester wrote:
On 08/27/2012 03:16 PM, jdow wrote:
ifconfig comes to mind.
{^_^}
$ ifconfig virbr0
virbr0Link encap:Ethernet HWaddr 52:54:00:EB:2D:7B
inet addr:192.168.122.1 Bcast:192.168.122.255 Mask:255.255.255.0
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:0 errors:0 dropped:0 overruns:0 frame:0
TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:0
RX bytes:0 (0.0 b) TX bytes:0 (0.0 b)
What am I looking for?
MTU:1500
This interface is not doing jumbo frames.
Betcha this shows the same thing:
cat /sys/class/net/virbr0/mtu
(Or find it under /sys/devices/virtual/net possibly.)
Mess with it carefully.
{^_^}
Re: jumbo frames?
man ifconfig
/MTU
mtu N This parameter sets the Maximum Transfer Unit (MTU) of an
interface.
Clint BowmanINTERNET: cl...@ecy.wa.gov
Air Quality Modeler INTERNET: cl...@math.utah.edu
Department of Ecology VOICE: (360) 407-6815
PO Box 47600FAX:(360) 407-7534
Olympia, WA 98504-7600
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Parcels:300 Desmond Drive, Lacey, WA 98503-1274
On Mon, 27 Aug 2012, Todd And Margo Chester wrote:
On 08/27/2012 03:16 PM, jdow wrote:
On 2012/08/27 14:37, Todd And Margo Chester wrote:
On 08/27/2012 01:57 PM, Carl Friedberg wrote:
-Original Message-
From: owner-scientific-linux-us...@listserv.fnal.gov [mailto:owner-
scientific-linux-users@listserv.fnal.gov] On Behalf Of Todd And Margo
Chester
Sent: Monday, August 27, 2012 4:49 PM
To: Scientific Linux Users
Subject: jumbo frames?
Hi All,
Can anyone tell me what this means?
just disable jumbo frames on centos host interface
ifcfg and ethernet switch.
Many thanks,
-T
> Todd and Margo Chester:
>
> I can give you some information.
>
> jumbo frames refer to a capability to send very large packets
> over gigabit Ethernet (somewhere near 9,000 bytes), as
> opposed to the traditional ~1500 byte packet size on
> traditional Ethernet.
>
> This only works between two end-points if every switch
> handling the frame/packet has jumbo frame capability
> enabled.
>
> There have been instances (I've run into them, but not
> on SL) where enabling jumbo frames can cause issues.
>
> So, since you didn't provide context on that piece of
> advice, I can't guess why they were suggesting
> disabling jumbo frames.
>
> Typically, jumbo frames are disabled by default (but,
> I don't know what the SL policy is).
>
> Carl
>
> Carl Friedberg
> www.about.me/carl.friedberg
> friedb...@comets.com
> www.comets.com
> Problems Solved
>
>
Where would I go to check on this? Is there a utility?
ifconfig comes to mind.
{^_^}
$ ifconfig virbr0
virbr0Link encap:Ethernet HWaddr 52:54:00:EB:2D:7B
inet addr:192.168.122.1 Bcast:192.168.122.255 Mask:255.255.255.0
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:0 errors:0 dropped:0 overruns:0 frame:0
TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:0
RX bytes:0 (0.0 b) TX bytes:0 (0.0 b)
What am I looking for?
Re: jumbo frames?
On 27 August 2012 14:48, Todd And Margo Chester wrote: > Hi All, > > Can anyone tell me what this means? > > just disable jumbo frames on centos host interface > ifcfg and ethernet switch. Well first of all. What is giving you this error or message? Jumbo frames are not usually turned on CentOS/Scientific Linux without some extra configuration (eg in /etc/sysconfig/network-scripts/ifcfg-eth0 or the likes.). To see if they are enabled on the system.. ifconfig eth0 and look for the MTU line. If it is 1500 that is standard. If it is 9000 then it has been configured to be such somehow. > Many thanks, > -T -- Stephen J Smoogen. "Don't derail a useful feature for the 99% because you're not in it." Linus Torvalds "Years ago my mother used to say to me,... Elwood, you must be oh so smart or oh so pleasant. Well, for years I was smart. I recommend pleasant. You may quote me." —James Stewart as Elwood P. Dowd
Re: jumbo frames?
-BEGIN PGP SIGNED MESSAGE- Hash: SHA512 On 08/27/2012 05:32 PM, Todd And Margo Chester wrote: > > $ ifconfig virbr0 > virbr0Link encap:Ethernet HWaddr 52:54:00:EB:2D:7B > inet addr:192.168.122.1 Bcast:192.168.122.255 Mask:255.255.255.0 > UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1 > RX packets:0 errors:0 dropped:0 overruns:0 frame:0 > TX packets:0 errors:0 dropped:0 overruns:0 carrier:0 > collisions:0 txqueuelen:0 > RX bytes:0 (0.0 b) TX bytes:0 (0.0 b) > > What am I looking for? MTU:1500 Your using the default MTU of 1500 bytes so you aren't using Jumbo frames. - -- Larry Brower, CCNA Fedora Ambassador - North America Fedora Quality Assurance lbro...@fedoraproject.org http://www.fedoraproject.org/ -BEGIN PGP SIGNATURE- Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org/ iQIcBAEBCgAGBQJQO/bBAAoJEPXCUD/44PWqVGgQAJv2l+j1pLfdeNQBQ9p3rZuU J3uDLZis04HbWOXc0akXnYA/+25TuBy5kuBTzYQLz8W7unf3/dH87o/3jVxVjCsd NnBGpoEOvMuOb5QxLIuLGdIz//BrbkD3/MJ64GY7G9ZLnH4fs5a70Czj/HMi4KQq GpQKNV0ZPYUp/DHTi24lFRSpqHkxCSshvZSJnqkUKzYjo9HDcIkhuRk120egIZ36 ViOxx4fRbuh3jClCRB15KI6xAUlaEae0PSTkTXNnO3LaCm67wiwpCa1t0dXsTERj tYYktQy4WrrUbdNVFeLuu5+2XIiP4neHY/jjDuX82gRC7acyrhWirMVJKiRVkZCE jTmmA2ef75wrVdsUtm+SnrR/73R1VVqUL3gYF/4ZlXornjcB13K36nwsSwqF9bDA E3uSWF8FYlpBv9X0HbtGv3UaVUsN2MEHCopTQTyuKvksIxxRf036OCe1HN4zyWBJ xzDMYNHN+I66HzSaZVrrcvULFPiUz0jqX0cGS6/s/+FGjteP8J2Et/OKE8ov7xbs BXPqE8iN7GYWd7ZIdIsByQjQR4gMXJdlBUEf9SR3R5RwFjCfowPW1sgJjDXqMpZ6 tMV68YyeNl7JRBX05f6Z+a4Y6mYu5B8dMw9jBVugU3g5EpOfP06BN41Npx7MsldD fK68I5OoJzf6niOXPaAQ =9OX+ -END PGP SIGNATURE-
Re: jumbo frames?
On 08/27/2012 03:16 PM, Alec T. Habig wrote: Todd And Margo Chester writes: Where would I go to check on this? Is there a utility? # ifconfig eth0 eth0 Link encap:Ethernet HWaddr 00:E0:81:B2:10:D7 inet addr:131.212.37.6 Bcast:131.212.37.255 Mask:255.255.255.0 UP BROADCAST RUNNING MULTICAST MTU:9000 Metric:1 RX packets:6914505 errors:0 dropped:0 overruns:0 frame:0 TX packets:3983544 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:1000 RX bytes:6511170177 (6.0 GiB) TX bytes:1440910442 (1.3 GiB) Interrupt:18 Memory:c420-c422 The MTU 9000 says it's on for me on this interface. # ifconfig eth2 eth2 Link encap:Ethernet HWaddr 00:E0:29:85:EF:AD inet addr:192.168.2.1 Bcast:192.168.2.255 Mask:255.255.255.0 UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1 RX packets:138324 errors:0 dropped:0 overruns:0 frame:0 TX packets:201726 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:1000 RX bytes:18886234 (18.0 MiB) TX bytes:154781925 (147.6 MiB) Interrupt:20 Base address:0x6000 in here, MTU's only 1500, so no jumbo frames. Hi Alex, $ ifconfig virbr0 virbr0Link encap:Ethernet HWaddr 52:54:00:EB:2D:7B inet addr:192.168.122.1 Bcast:192.168.122.255 Mask:255.255.255.0 UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1 RX packets:0 errors:0 dropped:0 overruns:0 frame:0 TX packets:0 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:0 RX bytes:0 (0.0 b) TX bytes:0 (0.0 b) It is the MTU, so no jumbo frames. Thank you! -T
Re: jumbo frames?
On 08/27/2012 03:16 PM, jdow wrote:
On 2012/08/27 14:37, Todd And Margo Chester wrote:
On 08/27/2012 01:57 PM, Carl Friedberg wrote:
-Original Message-
From: owner-scientific-linux-us...@listserv.fnal.gov [mailto:owner-
scientific-linux-users@listserv.fnal.gov] On Behalf Of Todd And Margo
Chester
Sent: Monday, August 27, 2012 4:49 PM
To: Scientific Linux Users
Subject: jumbo frames?
Hi All,
Can anyone tell me what this means?
just disable jumbo frames on centos host interface
ifcfg and ethernet switch.
Many thanks,
-T
> Todd and Margo Chester:
>
> I can give you some information.
>
> jumbo frames refer to a capability to send very large packets
> over gigabit Ethernet (somewhere near 9,000 bytes), as
> opposed to the traditional ~1500 byte packet size on
> traditional Ethernet.
>
> This only works between two end-points if every switch
> handling the frame/packet has jumbo frame capability
> enabled.
>
> There have been instances (I've run into them, but not
> on SL) where enabling jumbo frames can cause issues.
>
> So, since you didn't provide context on that piece of
> advice, I can't guess why they were suggesting
> disabling jumbo frames.
>
> Typically, jumbo frames are disabled by default (but,
> I don't know what the SL policy is).
>
> Carl
>
> Carl Friedberg
> www.about.me/carl.friedberg
> friedb...@comets.com
> www.comets.com
> Problems Solved
>
>
Where would I go to check on this? Is there a utility?
ifconfig comes to mind.
{^_^}
$ ifconfig virbr0
virbr0Link encap:Ethernet HWaddr 52:54:00:EB:2D:7B
inet addr:192.168.122.1 Bcast:192.168.122.255
Mask:255.255.255.0
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:0 errors:0 dropped:0 overruns:0 frame:0
TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:0
RX bytes:0 (0.0 b) TX bytes:0 (0.0 b)
What am I looking for?
Re: jumbo frames?
On 2012/08/27 14:37, Todd And Margo Chester wrote:
On 08/27/2012 01:57 PM, Carl Friedberg wrote:
-Original Message-
From: owner-scientific-linux-us...@listserv.fnal.gov [mailto:owner-
scientific-linux-users@listserv.fnal.gov] On Behalf Of Todd And Margo
Chester
Sent: Monday, August 27, 2012 4:49 PM
To: Scientific Linux Users
Subject: jumbo frames?
Hi All,
Can anyone tell me what this means?
just disable jumbo frames on centos host interface
ifcfg and ethernet switch.
Many thanks,
-T
> Todd and Margo Chester:
>
> I can give you some information.
>
> jumbo frames refer to a capability to send very large packets
> over gigabit Ethernet (somewhere near 9,000 bytes), as
> opposed to the traditional ~1500 byte packet size on
> traditional Ethernet.
>
> This only works between two end-points if every switch
> handling the frame/packet has jumbo frame capability
> enabled.
>
> There have been instances (I've run into them, but not
> on SL) where enabling jumbo frames can cause issues.
>
> So, since you didn't provide context on that piece of
> advice, I can't guess why they were suggesting
> disabling jumbo frames.
>
> Typically, jumbo frames are disabled by default (but,
> I don't know what the SL policy is).
>
> Carl
>
> Carl Friedberg
> www.about.me/carl.friedberg
> friedb...@comets.com
> www.comets.com
> Problems Solved
>
>
Where would I go to check on this? Is there a utility?
ifconfig comes to mind.
{^_^}
Re: jumbo frames?
On 08/27/2012 01:57 PM, Carl Friedberg wrote: -Original Message- From: owner-scientific-linux-us...@listserv.fnal.gov [mailto:owner- scientific-linux-users@listserv.fnal.gov] On Behalf Of Todd And Margo Chester Sent: Monday, August 27, 2012 4:49 PM To: Scientific Linux Users Subject: jumbo frames? Hi All, Can anyone tell me what this means? just disable jumbo frames on centos host interface ifcfg and ethernet switch. Many thanks, -T > Todd and Margo Chester: > > I can give you some information. > > jumbo frames refer to a capability to send very large packets > over gigabit Ethernet (somewhere near 9,000 bytes), as > opposed to the traditional ~1500 byte packet size on > traditional Ethernet. > > This only works between two end-points if every switch > handling the frame/packet has jumbo frame capability > enabled. > > There have been instances (I've run into them, but not > on SL) where enabling jumbo frames can cause issues. > > So, since you didn't provide context on that piece of > advice, I can't guess why they were suggesting > disabling jumbo frames. > > Typically, jumbo frames are disabled by default (but, > I don't know what the SL policy is). > > Carl > > Carl Friedberg > www.about.me/carl.friedberg > friedb...@comets.com > www.comets.com > Problems Solved > > Where would I go to check on this? Is there a utility?
Re: jumbo frames?
Todd And Margo Chester writes: > Can anyone tell me what this means? > > just disable jumbo frames on centos host interface > ifcfg and ethernet switch. MTU=9000 is a "jumbo frame". Lots of data stuck onto the same sized IP header means more data going through for the same administrative overhead. I think most times things default to 1500, so you have to go out of your way to set this up (I do in order to get 8k sized nfs packets through on our local net). Including the switches and routers: if I send a 9000 byte packet through and it hits a switch along the way which is set for 1500, it will chop it up into a lot of smaller packets before passing it along: destroying any performance advantage I'd hoped to get. Anyway: set the MTU to something smaller (more normal?) and "jumbo frames" are disabled, at least from a naive user's perspective. There are probably more subtle kernel network stack issues I'm not aware of. -- Alec Habig, University of Minnesota Duluth Physics Dept. ha...@neutrino.d.umn.edu http://neutrino.d.umn.edu/~habig/
jumbo frames?
Hi All, Can anyone tell me what this means? just disable jumbo frames on centos host interface ifcfg and ethernet switch. Many thanks, -T
Re: Enabling jumbo frames on VLAN
On 10/19/2011 06:06 PM, carlopmart wrote:
Hi all,
I have a SL6.1 server acting as a storage server (iscsi and nfs). Is it
possible to configure jumbo frames on a specific vlan or is it a stupid
question??
This host has two physical nics, but in one of them I have configured
vlans:
1: eth0: mtu 1500 qdisc pfifo_fast
state UP qlen 1000
link/ether 00:1f:29:55:92:b4 brd ff:ff:ff:ff:ff:ff
inet 172.25.50.12/27 brd 172.25.50.31 scope global eth0
inet6 fe80::21f:29ff:fe55:92b4/64 scope link
valid_lft forever preferred_lft forever
2: eth1: mtu 1500 qdisc pfifo_fast
state UP qlen 1000
link/ether 00:1f:29:55:92:b5 brd ff:ff:ff:ff:ff:ff
inet6 fe80::21f:29ff:fe55:92b5/64 scope link
valid_lft forever preferred_lft forever
3: eth1.10@eth1: mtu 1500 qdisc
noqueue state UP
link/ether 00:1f:29:56:44:6a brd ff:ff:ff:ff:ff:ff
inet 172.25.60.3/28 brd 172.25.60.15 scope global eth1.10
inet6 fe80::21f:29ff:fe56:446a/64 scope link
valid_lft forever preferred_lft forever
4: eth1.20@eth1: mtu 1500 qdisc
noqueue state UP
link/ether 00:1f:29:56:44:6a brd ff:ff:ff:ff:ff:ff
inet 10.1.1.5/27 brd 10.1.1.31 scope global eth1.20
inet6 fe80::21f:29ff:fe56:446a/64 scope link
valid_lft forever preferred_lft forever
Can I assign mtu=9000 only to eth1.20??
Thanks.
Sorry, stupid question. It is not possible.
--
CL Martinez
carlopmart {at} gmail {d0t} com
Enabling jumbo frames on VLAN
Hi all,
I have a SL6.1 server acting as a storage server (iscsi and nfs). Is
it possible to configure jumbo frames on a specific vlan or is it a
stupid question??
This host has two physical nics, but in one of them I have configured
vlans:
1: eth0: mtu 1500 qdisc pfifo_fast
state UP qlen 1000
link/ether 00:1f:29:55:92:b4 brd ff:ff:ff:ff:ff:ff
inet 172.25.50.12/27 brd 172.25.50.31 scope global eth0
inet6 fe80::21f:29ff:fe55:92b4/64 scope link
valid_lft forever preferred_lft forever
2: eth1: mtu 1500 qdisc pfifo_fast
state UP qlen 1000
link/ether 00:1f:29:55:92:b5 brd ff:ff:ff:ff:ff:ff
inet6 fe80::21f:29ff:fe55:92b5/64 scope link
valid_lft forever preferred_lft forever
3: eth1.10@eth1: mtu 1500 qdisc
noqueue state UP
link/ether 00:1f:29:56:44:6a brd ff:ff:ff:ff:ff:ff
inet 172.25.60.3/28 brd 172.25.60.15 scope global eth1.10
inet6 fe80::21f:29ff:fe56:446a/64 scope link
valid_lft forever preferred_lft forever
4: eth1.20@eth1: mtu 1500 qdisc
noqueue state UP
link/ether 00:1f:29:56:44:6a brd ff:ff:ff:ff:ff:ff
inet 10.1.1.5/27 brd 10.1.1.31 scope global eth1.20
inet6 fe80::21f:29ff:fe56:446a/64 scope link
valid_lft forever preferred_lft forever
Can I assign mtu=9000 only to eth1.20??
Thanks.
--
CL Martinez
carlopmart {at} gmail {d0t} com
