FreeBSD 13.0 terrible performance in KVM

[dashdruid]

Hello,

I have reinstalled it with GPT/ZFS and your right it's much better. Same search taking 3-6 seconds so I have deleted now all my old UFS based FreeBSD images.

I wonder how I didn't notice this earlier because I had 12.0, 12.2 base images and now that I retested them they had the exact same issues. I guess after the stuff is loaded into memory it doesn't matter anymore. This must be something related to the virtual disk access.

I was not thinking on using ZFS due to the higher memory recommendations, some of these VMs I using them for tiny tasks like DNS server and I don't give them more than 256, 512MB of ram. Also I don't take advantage of snapshotting either since it's a VM and it's either snapshotted or I just have base images and copy them when creating new VMs.

Well UFS is on it's way out anyway.

‐‐‐‐‐‐‐ Original Message ‐‐‐‐‐‐‐
On Saturday, April 24, 2021 3:03 PM, Jeff Love jl at burgh.net wrote:

> I'm running 12.2 and 13.0 on KVM using virtio and zfs. I am not having
> disk I/O issues.
> Jeff Love
> On 4/24/21 5:25 AM, dashdruid via freebsd-stable wrote:
>
>> Hello List,
>> I hope some other folks out there running FreeBSD on KVM as well. I set up a base VM while doing so I noticed that the disk operations are very slow. Many times I edit a file in vim or try to run a command there is a huge lag.
>> I use UFS as the root filesystem. To have something to compare it with I have tested it against an OpenBSD 6.6 VM on the same host, same hardware. both have 1 vCPU and 1GB of ram, 20GB virtual disk (they are exactly on the same physical disk no raid or anything to have a fair comparison).
>> Here is an example simple file search time for a non-existent file:
>> FreeBSD 13
>> time find / -name cacert.pem
>> real 0m30.656s
>> user 0m0.516s
>> sys 0m3.938s
>> Second run even worse
>> real 2m38.618s
>> user 0m0.711s
>> sys 0m6.882s
>> While on the OpenBSD VM I get
>> time find / -name cacert.pem
>> real 0m2.258s
>> user 0m0.290s
>> sys 0m1.970s
>> The amount of data is about the same on both systems but I would not consider this a "slight" performance degradation. If the base system is so slow then imagine putting Apache and other servers on top of it. Did anyone run into this?
>> Unless there is a definitive solution I will opt out to using other BSD variants.
>> freebsd-stable at freebsd.org mailing list
>> https://lists.freebsd.org/mailman/listinfo/freebsd-stable
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>
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