Common Server issues – FAQs and answers from those in the know
Seeking measurements of server request rate and utilization in order to real-world-validate a new capacity planning technique [closed]
26 April 2026 @ 4:50 pm
Seeking measurements of server request rate and utilization in order to validate a new capacity planning technique.
Do you have one or more servers which experience an hour+ peak period
with relatively high and consistent request rate and utilization?
On one of them, could you record the request rate and system
utilization each second for that hour?
Without revealing any company secrets, could you do calculations on the measurement data or provide the data to me to analyze?
Why ask?
There is a mathematically-derived estimation technique which needs experimental validation or invalidation.
The technique uses measurements of utilization to derive a specific transaction rate and resource per transaction which could cause that.
The validation exercise requires also recording the transaction rates.
Mathematically, given
The statistical mean and variance of utilization
and
A
How do I block external user access to a web server directory without preventing internal apache/web site access during normal functionality?
26 April 2026 @ 4:30 pm
How do I block external user access to a web server directory without preventing internal website & apache access during normal authorized functionality using only the .htaccess file?
I am trying to ensure logged on users can do internal searches in this directory using normal web site links, but want to block direct URL access to this directory for any users, logged in or not.
I have info on creating .htpasswd, but that would be very large and require daily updates (perhaps from a SQL query) and wondering if there is a way around this.
Everything I have tried either disallows both or allows both.
on debian 12, a faulty ip failover config. Adding an ipv4 gets ipv6 not working
26 April 2026 @ 4:16 pm
I'm using debian 12 and want to configure a failover ipv4 by
editing directly /etc/netplan/50-cloud-init.yaml
This content works well giving functional ip, 1 ipv4/32 and 1 ipv6/128
network:
version: 2
ethernets:
eno1:
dhcp4: true
addresses: ['2001:xxxx:xxxx:xxxx:xxxx:1/128']
gateway6: 2001:xxxx:xxxx:xxxx:ff:ff:ff:ff
nameservers:
addresses: [64:xx:xx.1]
routes:
- to: 2001:xxxx:xxxx:xxxx:ff:ff:ff:ff/128
via: '::'
accept-ra: false
match:
macaddress: 50:50:50:50:50:50
set-name: eno1
When I add this after the above if the yaml config file, I get the new ipv4 working but I lose the ipv6
which was working well before.
network:
version: 2
ethernets:
NETWORK_INTERFACE:
dhcp4: true
match:
macaddress: 50:50:50:50:50:50
set-name: eno1
addresses:
- 64:xx:yy.2/32
What am I doing wrong ?
ps: I know that there are mandatory spaces in the config.
If there is only one configuration by interface, how to fusion the two
Ganesha NFS setup with cephadm: The requested image's platform does not match the detected host platform
26 April 2026 @ 2:28 pm
I'm trying to make the contents of my Ceph cluster available to clients via NFS. According to the doc, a fairly simple ceph command should do the job:
sudo ceph nfs cluster create clusterbox_nfs --ingress --virtual-ip 10.20.0.20
The cluster nodes are equipped with ARM CPUs (Rockchip RK3588). This fact seems to play an important role here.
The command seems to work in the first place:
mixtile@blade3n1:~$ sudo ceph orch ls --service_name=nfs.clusterbox_nfs
NAME PORTS RUNNING REFRESHED AGE PLACEMENT
nfs.clusterbox_nfs ?:12049 1/1 3m ago 4m count:1
mixtile@blade3n1:~$ sudo ceph orch ls --service_name=ingress.nfs.clusterbox_nfs
NAME PORTS RUNNING REFRESHED AGE PLACEMENT
ingress.nfs.clusterbox_nfs 10.20.0.20:2049,9049 0/4 - 5m count:2
Ceph web dashboard can't display OSDs and devices
26 April 2026 @ 11:58 am
I've now got my Ceph cluster almost ready to use, but in the web dashboard, I don't see any of the four OSDs I've created. Neither do I find any of my NVMe drives the OSDs reside on:
Error message: No devices (HDD, SSD or NVME) were found. Creation of OSDs will remain disabled until devices are added.
Here is what I get on the command line:
mixtile@blade3n1:~$ sudo ceph osd tree
[sudo] password for mixtile:
ID CLASS WEIGHT TYPE NAME STATUS REWEIGHT PRI-AFF
-1 29.80798 root default
-9 7.45200 host blade3n1
3 ssd 7.45200 osd.3 up 1.00000 1.00000
-7 7.45200 host blade3n2
2 ssd 7.45200 osd.2 up 1.
Error message: No devices (HDD, SSD or NVME) were found. Creation of OSDs will remain disabled until devices are added.
Here is what I get on the command line:
mixtile@blade3n1:~$ sudo ceph osd tree
[sudo] password for mixtile:
ID CLASS WEIGHT TYPE NAME STATUS REWEIGHT PRI-AFF
-1 29.80798 root default
-9 7.45200 host blade3n1
3 ssd 7.45200 osd.3 up 1.00000 1.00000
-7 7.45200 host blade3n2
2 ssd 7.45200 osd.2 up 1.Enable IPv6 connectivity in Windows Sandbox? [migrated]
26 April 2026 @ 12:44 am
I am having troubles resolving IPv6 hosts inside Windows Sandbox. I am getting DNS_PROBE_FINISHED_NXDOMAIN errors for websites, I also cannot ping IPv6 hosts in Sandbox, getting
Ping request could not find host website.com. Please check the name and try again.
In host system ping works fine.
All of the solutions in the web and here on SF (1, 2, 3, 4) circle around the changing network adapter type from public to private and changing discoverability to On
Install CakePHP [closed]
25 April 2026 @ 4:42 am
I need help to install CakePHP. This is my code:
Its to be used on h() in the code
<?=
require_once 'app/config/config.php';
error_reporting(E_ALL);
ini_set('display_errors', '1');
$UserName = $_POST['UserName'];
$PassPhrase1 = $_POST['PassPhrase1'];
if (@!$UserName) {
echo "Användarnamn (saknas)!";
}
if (@!$PassPhrase1) {
echo "Lösenord saknas!";
}
if (@isset($UserName, $PassPhrase1) AND !$_POST['submit']) {
// Hello, World!
while (h($_POST['submit'])) {
echo "INSERT INTO users (UserName, PassPhrase) VALUES ('$UserName', '$PassPhrase1')";
echo "Test";
break;
}
} ?><?= echo "any extra mambo jambo here!"; ?><?= echo "even more"; ?>
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta http-equiv="X-UA-Compatible" content="IE=edge">
<meta name="viewport" content="width=de
How to solve the 429 rateLimitExceeded issue [closed]
24 April 2026 @ 11:52 pm
I am new to this. Error free with the free 90 day trail on google cloud using simple API, but now with paid basic plan every run result in 429 resource exhausted error. what the best solution to get this to work again... ?
Cloudbase-init doesn't assign IP to Windows 2019
24 April 2026 @ 4:43 pm
I use Ansible to provision Windows VMs on VCenter and we currently evaluating cloudbase-init.
With our workflow it's not possible to know the MAC of the VM before we build the VM. So, our metadata look like this:
network:
version: 2
ethernets:
id0:
match:
name: "Ethernet*"
addresses:
- 192.168.0.100
gateway4: 192.168.0.254
nameservers:
addresses:
- 192.168.0.1
- 192.168.0.2
However, cloudbase-init doesn't configure the IP and the logs have the following:
INFO cloudbaseinit.init [-] Executing plugin 'NetworkConfigPlugin'
ERROR cloudbaseinit.init [-] plugin 'NetworkConfigPlugin' failed with error ''NoneType' object has no attribute 'lower''
ERROR cloudbaseinit.init [-] 'NoneType' object has no attribute 'lower': AttributeError: 'NoneType' object has no attribute 'lower'
ERROR cloudbaseinit.init Traceback (most recent call last):
ERROR cloud
Why my QEMU VM see two displays?
24 April 2026 @ 3:57 pm
I am running Zorin Linux 18 in a QEMU vm that uses:
qemu-system-x86_64 -machine pc-q35-11.0 \
-enable-kvm -m 16G -smp 4 -cpu host \
-audiodev pa,id=snd0 \
-device intel-hda -device hda-duplex,audiodev=snd0 \
-device virtio-gpu-pci,hostmem=2G \
-drive file=/mnt/wd26TbLinux/qemu_vms/zorinux/zorinux.qcow2,format=qcow2 \
-netdev bridge,id=hn0,br=br0,helper=/opt/qemu_v11.0.0/libexec/qemu-bridge-helper \
-device virtio-net-pci,netdev=hn0,id=nic1 \
-boot order=c
I am using qemu 11 and my VM sees 2 displays...
Why?
See Andrei answer. I just wanted to add that to stop the vga "offered" by the "machine" it is necessary to place
-vga none \
as with
qemu-system-x86_64 \
-machine q35,accel=kvm \
-vga none \
-nographic \
-serial mon:stdio \
Thanks in advance