Skip to main content
Share Your Experience: Take the 2024 Developer Survey
19 votes

how to tell if NIC has multiqueue enabled?

ethtool -l <interface> will display the status of queues associated with an interface, if that interface's driver supports such a thing. In ethtool-land, multiqueue is indicated by "channels". ...
Jesse Adelman's user avatar
10 votes

10/20/40Gbps nginx large files caching webserver [20Gbps reached]

Disclaimer: The same advice applies to all services pushing more than 10Gbps. Included but not limited to load balancers, caching servers, webservers (HAProxy, Varnish, nginx, tomcat, ...) What you ...
user5994461's user avatar
  • 3,029
9 votes
Accepted

Converter for RJ45 port to SFP+

The regular 'copper'/RJ-45 connector pin-outs cannot provide the power needed to drive the optics to allow you to do what you want to - you'll have to use a media converter or just swap out the NIC ...
Chopper3's user avatar
  • 102k
6 votes
Accepted

Do 10GbE SFP transceivers need to match?

Simple answer: No. You don't need to match Brand or Model, 10GbE is usually not as picky as FC.
bjoster's user avatar
  • 4,967
4 votes

Cannot get over 100k iops from storage on 10g network on 4k random blocks

You're saturating the PCIe bus with iowaits, don't look at CPU load. 40g or 100g would help a bit: your problem is latency. You'll never come close to approaching sequential speeds over a NIC doing 4k ...
user2045916's user avatar
4 votes

Is there any cheap way to convert from CX4 to RJ45?

CX4 is a dead connector and fell into disuse a long time ago. The ProCurve 2900 went end-of-life ~13 years go. Your internet provider is giving you a 10GbE handoff, but you can use a 1GbE port on ...
ewwhite's user avatar
  • 198k
3 votes
Accepted

Network performance with an i7 6700 Skylake

The CPU can surehyl handle 10g of traffic per port un a DECENT card (note: you say nothing about brand - brand of the network card is VERY Important here). The question is whether it can PROCESS it, ...
TomTom's user avatar
  • 52k
3 votes

Serializing pcap file into 4B chunks

You can split a file into multiple files of whatever size you like using the split command. Here is an example where I split a previously created pcap file into 4 byte chunks: /tmp/wat$ ls -l total 4 ...
kasperd's user avatar
  • 30.7k
3 votes

10GBase-T on Cat5e cabling

Take a look and see if there are any errors accruing on the switch ports or the server's NIC ports - ideally before/after an extended session sending a lot of traffic in both directions. If the ...
rnxrx's user avatar
  • 8,163
3 votes
Accepted

Is it possible to have a link between a 10GbE NIC and 1GbE Switch with a SFP+ DAC?

I'd suggest a pair of Copper SFP adapters to connect things temporarily. The cable you have likely isn't compatible. The PowerConnect 2824 doesn't have SFP+ ports (only SFP).
ewwhite's user avatar
  • 198k
3 votes

How to achieve multiple NFS/TCP connections to the same server?

Starting from linux kernel 5.3 a new mount option "nconnect=X" is available, where X specifies the number of TCP connections to the server to use.
kofemann's user avatar
  • 4,939
3 votes
Accepted

Can you mix 10gb and Infiniband for iScsi storage target

Possible? Yes. Reasonable? Maybe. Safe? Depends. Ethernet and Infiniband are not compatible - but they can both run TCP/IP, so iSCSI on top can work. The easiest solution is a multi-protocol router ...
Zac67's user avatar
  • 11.9k
3 votes
Accepted

linux 10gbe ixgbe (intel X550T) slow at 420mbyte/s max, p2p lan cat8 1m, tried ethtool and ifconfig options to no avail

Solved, not a software problem, my computer has way too many drives, PCI legacy devices and a GPU too, that leaves me without x4 available PCIe lanes for the card, it is throttled down to x1, which on ...
tinfoil3d's user avatar
3 votes
Accepted

Very slow write speed (NVME drive) on 10G network

This answer was inspired by comment by @shodanshok, who commented (so I can't upvote his contribution -- posting an answer instead) Edit 2021/06/09 - iperf3 developers identified a possible problem; ...
roman's user avatar
  • 191
2 votes

Why would I choose Copper over SFP+ for 10GbE?

Comparing SFP+ to 10GBASE-T. Pros of SFP+ Lower latency (though unless you are in HFT or similar it's likely negligable) Lower power consumption Cheaper NICs and switches More choice of connected ...
Peter Green's user avatar
  • 4,346
2 votes
Accepted

How to connect a Juniper EX4500 to netapp X1107A

You asked specifically for the "cheapest" way and I'm going to do you one better and make it simpler. If the distance isn't too great, I'd get what's referred to as a "DAC (Direct Attached Copper)" ...
SpacemanSpiff's user avatar
2 votes

how to tell if NIC has multiqueue enabled?

You can see how many queues that you have available with: ethtool -S [interface] If you have multiple queues enabled, they will show up. In addition you can watch traffic on the rx (tx) queues with ...
Robert Frisbee's user avatar
2 votes
Accepted

How did 10gbe happen without increasing the number of wires in the cable?

See this page for a brief history of Ethernet. Your question infers that you're only concerned about four-pair twisted pair cable, in which case you can search for "8P8C" to see the many different ...
EEAA's user avatar
  • 110k
2 votes

LACP bandwidth of multiple connections from single fast link

Replace LACP to Roundrobin bonding mode (mode=0). Change Cisco port-channel mode to on. Before all remove all interfaces from this port-channel group. Why i advice you to use RR (round robin)? LACP ...
Mikhail Khirgiy's user avatar
2 votes
Accepted

LACP bandwidth of multiple connections from single fast link

This is dependend on the load-balancing algorithm which decides which connections should always be on the same wire. I'm not familiar with Meraki in this regard but for Cisco the default would be ...
pacey's user avatar
  • 3,823
2 votes
Accepted

SFP+ to 10GbE RJ45

SFP+ is a slot designed primerally for fiber optic transciver modules. It is also possible to directly connect two SFP+ devices using a "SFP+ Direct attatch" cable. Unfortunately 10GBASE-T ...
Peter Green's user avatar
  • 4,346
2 votes
Accepted

want to build a private 10 Gbps backplane

The Intel 82599 is a 2 port 10GE controller. QSFP is a 40GE connection mechanism. QSFP is a 40G connection mechanism but can operate in a mode where 4 10G lanes are broken out. Absent any other ...
rnxrx's user avatar
  • 8,163
2 votes
Accepted

Why the bandwidth is not ~10G?

It turn out that the problem was related to how Windows 7/8 clients manage the TCP Window scaling. By default, Windows client editions prefer relatively small TCP window, prioritizing latency vs ...
shodanshok's user avatar
  • 50.9k
2 votes
Accepted

ESXI, pfSense, 10gbE

The pfSense VM has quite a bit of overhead to fight with - ingress packets go through the host NIC, host vSwitch, are copied to the VM, pass the guest stack, are processed and egress packets take the ...
Zac67's user avatar
  • 11.9k
2 votes
Accepted

How to connect MD3800i (iSCSI 10 GbE) to PowerConnect 8132F (SFP+ 10 GbE)

You are conflating two terms. You do not have an "iSCSI port", you have a 10GBASE-T port and an SFP+ port. You need to know how to connect those two things. iSCSI is the Layer 7 protocol. You're ...
Mark Henderson's user avatar
2 votes

Do 10GbE SFP transceivers need to match?

Each device will need a transceiver that it's happy with, but they don't need to match at opposite ends of the link. (several manufacturers, and Cisco is one, read out the data in the module's EEPROM ...
alex.forencich's user avatar
2 votes
Accepted

What is a 4x 10gbe QSFP-QSFP cable?

QSFP means, literally, "Quad SFP" connector. In other words, it is a single SFP connector that carries four link. From wikipedia: The Quad Small Form-factor Pluggable (QSFP) is a compact, hot-...
shodanshok's user avatar
  • 50.9k
2 votes

How many "joins" allowed for 10GbE copper?

My guess is that "link segment" means cable between active components, not jacks. This is correct. You need a device that will terminate and retransmit (not just amplify) the ethernet frame. This is ...
Joel Coel's user avatar
  • 13k
2 votes

What to expect from a 10Gbs fiber optic network of one server connected directly to 4 clients?

I have a fiber optic network of one server connected directly to 4 clients(they are not connected to each other) I'm assuming you're not using a switch. The network is suppose to support up to ...
Zac67's user avatar
  • 11.9k
2 votes

Very slow write speed (NVME drive) on 10G network

Using my 2 servers connected over 10Gbit ethernet and your way of testing shows that the NVMe drives I use are slower than I expected when using iperf3. I think you might see the disks are actually ...
Marco's user avatar
  • 307

Only top scored, non community-wiki answers of a minimum length are eligible