Hello, IPerf will simply tell you the bandwidth and the open pipe between 2 VMs, so I don’t think that it’s depends on disk performance, it’s better to check the network QoS at every layer, VR and VM.
Vivek Kumar Sr. Manager - Cloud & DevOps TechOps | Indiqus Technologies vivek.ku...@indiqus.com <mailto:vivek.ku...@indiqus.com> www.indiqus.com <https://www.indiqus.com/> > On 07-Jul-2023, at 9:44 PM, Granwille Strauss <granwi...@namhost.com.INVALID> > wrote: > > Hi Levin > > Thank you, I am aware of network offering, the first thing I did was make > sure it was set to accommodate the KVM's entire 1 Gbps uplink. But now that I > think if it iperf test prevousily were always stuck on 50 Mbps, but this is > because of the write speeds on the disk at least that's what I believe causes > the network bottle neck. I will double-check this again. > > But there is some sort of limit on the VM disk in place. FIO tests show that > write speeds are in the range of 50 - 90 MB/s on the VM, while fio test > confirms on the KVM its over 400 MB/s. > > On 7/7/23 18:08, Levin Ng wrote: >> Hi Groete, >> >> Forgot to mention, when you are talking about file copies between remote >> server, you need to aware there are network QoS option in the offering, make >> sure the limits correctness. Do iperf test prove that too, test between >> server and via virtual router. Hope you can narrow down the problem soon. >> >> Regards, >> Levin >> >> On 7 Jul 2023 at 16:40 +0100, Granwille Strauss <granwi...@namhost.com> >> <mailto:granwi...@namhost.com>, wrote: >>> Hi Levin >>> Thank you, yes I leave IOPs empty. And the KVM host has SSDs in a hardware >>> RAID 5 configuration, of which I am using local storage pool, yes. I will >>> run fio test and also playing around with the controller cache settings to >>> see what happens and provide feedback on this soon. >>> On 7/7/23 17:23, Levin Ng wrote: >>>> HI Groete, >>>> >>>> Should you run a fio test on the VM and the KVM host to get a baseline >>>> first. SSD are tricky device, when it fill up the cache or nearly full, >>>> the performance will drop significantly, especially consumer grade SSD. >>>> There are option to limit IOPs in ACS offering setting, I believe you >>>> leave it empty, so it is no limit. When you talking about KVM uses SSDs, I >>>> think you are using Local Disk Pool right? If you have RAID controller >>>> underlying, try toggle the controller cache, SSD may perform vary on >>>> different disk controller cache setting. >>>> >>>> Controller type scsi, or virtio performance are similar, no need to worry >>>> about it. Of coz, in general, using RAW format and thick provisioning >>>> could get a best io performance result, but consume space and lack of >>>> snapshot capabliblity , so most the time it is not prefer go this path. >>>> >>>> Please gather more information first >>>> >>>> Regards, >>>> Levin >>>> On 7 Jul 2023 at 15:30 +0100, Granwille Strauss >>>> <granwi...@namhost.com.invalid> <mailto:granwi...@namhost.com.invalid>, >>>> wrote: >>>>> Hi Guys >>>>> Does Cloudstack have a disk write speed limit somewhere in its setting? >>>>> We have been transferring many files from remote servers to VM machines >>>>> on our Cloudstack instance and we recently noticed that the VM write >>>>> speeds are all limited to about 5-8 MB/s. But the underlying hardware of >>>>> the KVM uses SSDs capable of write speeds of 300 - 600 MB/s. My disk >>>>> offering on my current vms are set to "No Disk Cache" with thin >>>>> provisioning, could this be the reason? I understand that "Write Back >>>>> Disk Cach" has better write speeds. Also I have VMs set as virtio for its >>>>> disk controller. What could I be missing in this case? >>>>> -- >>>>> Regards / Groete >>>>> >>>>> Granwille Strauss // Senior Systems Admin >>>>> >>>>> e: granwi...@namhost.com <mailto:granwi...@namhost.com> >>>>> m: +264 81 323 1260 >>>>> w: www.namhost.com <http://www.namhost.com/> >>>>> >>>>> >>>>> >>>>> >>>>> Namhost Internet Services (Pty) Ltd, >>>>> 24 Black Eagle Rd, Hermanus, 7210, RSA >>>>> >>>>> >>>>> The content of this message is confidential. If you have received it by >>>>> mistake, please inform us by email reply and then delete the message. It >>>>> is forbidden to copy, forward, or in any way reveal the contents of this >>>>> message to anyone without our explicit consent. The integrity and >>>>> security of this email cannot be guaranteed over the Internet. 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