Limit bandwidth

In September’s Cumulative Update (KB5017316), which was released on 13th September 2022, Microsoft included some new Cluster Parameters related to Live Migration. This is an important change you should be aware of as, by default, it’ll set the number of concurrent live migrations to 1 and set a bandwidth limit for live migration to 25% of the total SMB / RDMA BandwidthWhat are the new settings?The new Cluster Properties are:MaximumParallelMigrations – sets the number of parallel live migrations between nodesSetSMBBandwidthLimit – turns the limit on or offSMBBandwidthLimitFactor – sets the bandwidth limit for live migrationWhat the values mean:MaximumParallelMigrations: 1 = 1 concurrent live migration at a time, 2 = 2 live migrations at a time, etc. Default = 1SetSMBBandwidthLimit: 0 = disable, 1 = enable. Default 1SMBBandwidthLimitFactor: 0 – 10,000. Default 2500. Divide this by 100 and you get the Percentage reservation calculation. So 2500 = 25%You can view these settings on your cluster by running the following command:get-cluster | fl MaximumParallelMigrations, SetSMBBandwidthLimit, SMBBandwidthLimitFactorWhy was this change made?To protect clusters and cluster nodes from lost communication due to live migrations taking all the SMB bandwidth.The cluster wide SMB bandwidth limit and factor are to control automatically setting an SMB bandwidth limit for cluster traffic. The default will reserve 25% of the SMB bandwidth between nodes for the cluster, so live migrations traffic doesn’t saturate the storage / SMB network and cause instability.Changing the DefaultsIf you are confident your cluster(s) can handle more parallel live migrations and / or a higher bandwidth limit than the deafults, then you can adjust these new parameters as per the below examples:Set the concurrent live migrations to 2:(Get-Cluster).MaximumParallelMigrations = 2Turn off the bandwidth limit:(Get-Cluster).SetSMBBandwidthLimit = 0Set the bandwidth limit percentage: to 50%(Get-Cluster).SMBBandwidthLimitFactor = 5000Bandwidth LimitsFor bandwidth limits to work, which has always been the case, you’ll need the role installing on all the nodes: FS-SMBBWYou’ll also need to set the Live Migration performance option to SMB on each node:Set-VMHost -VirtualMachineMigrationPerformanceOption SMBSince the new cluster bandwidth limit parameter is a factor (SMBBandwidthLimitFactor) then it calculates a value in Bytes Per Second for the set percentage of the overall SMB Bandwidth available (usually your Storage RDMA Network) and uses that value to set the SmbBandWithLimit.The below example shows you what this looks like with the default 25% on a Cluster with 2 x 10GbE Adapters:As you can see the Bandwidth Limit is set to a value of 687500000Bps which is 5.5Gbps. This is slightly more than 25% of the overall bandwidth, however, and I found that this additional ‘margin’ increases in relation to the Adapters having a higher link speed. In the above example we have a total of 20Gbps over the 2 x 10GbE Adapters and 25% of that is 5Gbps (or 625000000Bps). I guess this is because the value is based on a factor!?Below are examples of what the bandwidth value is set to for 10, 40, and 100Gbps Adapters:* 4 x is being used as the default is 25% so 4 x = 100%**

Hello,I've downloaded a trial version to limit the bandwidth allowed for each user on a school network. I've created only one rule and it works very well and is very simple to configure on a getaway computer with internal bridging.Unfortunately, if I add P2P detection to this rule, the bandwidth is not throttle anymore and a PC with utorrent can use the full bandwidth.Here is the rule I've configured:Name : Limit TestDirection : bothProtocol : IPv4 basedRate limit: 100000:30000 (bytes/s)Network interface (the one directly connected to the ISP router)Source/Destination : AnySource Port : Destination Port : AnyTracking : IP address : Own rate limit and quota for each sourceNo penalty and no user info.If no DPI matching is configured for this one rule, the bandwidth is throttle to 100 KB (test done with speedtest.net, and other downoloading sites)If DPI matching (P2P only) is enabled, the bandwidth is not limited anymore, direct downloads or torrents download operate at full speed.How can I manage to simultaneously limit the bandwidth available per computer and forbid torrent traffic.Thanks in advance.

Bps, drop rate 0000 bps Match: dscp 7 af11 (10) Queueing queue limit 125 packets (queue depth/total drops/no-buffer drops) 0/22746/0 (pkts output/bytes output) 140102835/200267445037 bandwidth remaining 1% Class-map: class-default (match-any) 886017070 packets, 990471861604 bytes 30 second offered rate 598693000 bps, drop rate 0000 bps Match: any Queueing queue limit 40000 packets (queue depth/total drops/no-buffer drops) 0/0/0 (pkts output/bytes output) 886012710/990470128719 bandwidth remaining 49% The queue limit of 125 packets in the BULK class is most likely the reason packets are dropping; the queue is likely maxed out.Increasing the size of that queue might address the drops, but that might not actually be ideal. It is a complicated issue with a lot of trade offs. Thank you Joseph Doherty, for your post here and in several other places, which have been informative. "The queue limit of 125 packets in the BULK class is most likely the reason packets are dropping; the queue is likely maxed out."Well, I would say that's what IS happening, at least during traffic bursts."Increasing the size of that queue might address the drops, but that might not actually be ideal."Certainly true. However, unless your QoS policy's purpose is to "penalize" that traffic class, again, 125 packets on a 3 Gbps circuit, is very small. Keep in mind, increasing the queue limit will likely reduce drops and raise your overall average utilization (i.e. taking advantage of otherwise unused bandwidth), but it should not be adverse to your other traffic because of the minimal bandwidth allocation (again, it takes advantage of otherwise unused bandwidth).I see your reply is before my prior reply, so if you're concerned about increasing your QOS-BULK queue-limit, you're probably terrorfied of the policy I suggested, but it will likely do "better" for what you're likely trying to accomplish. Ah, from your stats, all the drops are in your QOS-BULK class, which isn't surprising as it's only guaranteed 1% of the bandwidth and a queue limit of 125 packets, the latter is likely very "shallow" for a 3Gbps WAN connection.There's two (usual) schools of thought about queue limits. One school proposes, queue resources should correspond to