All socks have terrible slow filesystems even 10 years old market pc runs faster.
Example linux swap is terrible slow from sd-card.
javas biggest problem is and has always been garbage collector it makes the software really cpu depended and on weak systems the performance is poor.
For a pure performance I would go for the small size embedded pc's.
Java is reasonable if you have alot of memory, strong CPU and the application loads as match as possible at startup.
Had some free time to toy around with Orange Pi Zero
Used a image "Armbian_5.26_Orangepizero_Ubuntu_xenial_dev_4.10.0.img" build with 'compile.sh BRANCH=dev BOARD=orangepizero KERNEL_ONLY=no PROGRESS_DISPLAY=plain RELEASE=xenial BUILD_DESKTOP=no'
- which should not do anything special ?
1) First steps
- run upgrades and normal tweaking (changed hostname, disabled ipv6, changed ntp, changed time-zone, generated correct locale)
2) Ensure that WLAN0 is working as client
- using 'nmtui' created a new connection to my desktop WLAN router
- disabled auto connect from eth0
- reboot with serial connection
- run example speedtest-cli to see that the driver do work
3) Removed the client profile and redo the eth0 for auto connection
4) I used these lines to create the sample profile but them afterwards tweaked it around with nmtui 'edit profile'
nmcli c add type wifi ifname wlan0 con-name ap-wlan0 autoconnect no ssid zmserver
nmcli connection modify ap-wlan0 802-11-wireless.mode ap 802-11-wireless.band bg ipv4.method shared
nmcli connection modify ap-wlan0 wifi-sec.key-mgmt wpa-psk
nmcli connection modify ap-wlan0 wifi-sec.psk "password"
nmcli connection up ap-wlan0
Key points here are 802-11-wireless.mode ap and shared
- shared means that network manager creates "internet-connection sharing" like MacOS and Windows wizards
- you cannot give dns-server or any other setting while using the shared - selection
Ensure that the "automatically connect" is selected to make sure that the connection is started when booted
I do have the basic nat lines enabled with 'iptables-persistent'
sh -c "echo 1 > /proc/sys/net/ipv4/ip_forward"
iptables -t nat -A POSTROUTING -o eth0 -j MASQUERADE
iptables -A FORWARD -i eth0 -o wlan0 -m state --state RELATED,ESTABLISHED -j ACCEPT
iptables -A FORWARD -i wlan0 -o eth0 -j ACCEPT
root@iothub1:/etc/NetworkManager/system-connections# more AP
# nmcli d
DEVICE TYPE STATE CONNECTION
eth0 ethernet connected Wired connection 1
wlan0 wifi connected AP
lo loopback unmanaged --
# nmcli c
NAME UUID TYPE DEVICE
AP 8e0bb6d9-52f9-4000-bbfa-d49db6790598 802-11-wireless wlan0
Wired connection 1 b9e400ce-f567-3f12-b459-366adc05a7f2 802-3-ethernet eth0
eth0 Link encap:Ethernet HWaddr 02:42:13:81:f5:29
inet addr:192.168.88.206 Bcast:192.168.88.255 Mask:255.255.255.0
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:45505 errors:0 dropped:0 overruns:0 frame:0
TX packets:28178 errors:0 dropped:0 overruns:0 carrier:0
RX bytes:66887562 (66.8 MB) TX bytes:2051800 (2.0 MB)
lo Link encap:Local Loopback
inet addr:127.0.0.1 Mask:255.0.0.0
UP LOOPBACK RUNNING MTU:65536 Metric:1
RX packets:0 errors:0 dropped:0 overruns:0 frame:0
TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
RX bytes:0 (0.0 TX bytes:0 (0.0
wlan0 Link encap:Ethernet HWaddr 12:42:13:81:f5:29
inet addr:10.42.0.1 Bcast:10.42.0.255 Mask:255.255.255.0
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:27567 errors:0 dropped:0 overruns:0 frame:0
TX packets:44475 errors:0 dropped:0 overruns:0 carrier:0
RX bytes:1901813 (1.9 MB) TX bytes:67699829 (67.6 MB)
# iwconfig wlan0
wlan0 IEEE 802.11 Mode:Master Tx-Power=20 dBm
Retry short limit:7 RTS thr:off Fragment thr:off
Does it work ==> YES
Is it fast ==> NO
Is it realiable ==> DO NOT KNOW
Feb 18 16:25:35 iothub1 wpa_supplicant: wlan0: AP-STA-DISCONNECTED 78:45:61:ee:43:47
Feb 18 16:25:35 iothub1 kernel: [ 1723.628815] ieee80211 phy0: vif 0: set_key cmd 1
Feb 18 16:25:35 iothub1 wpa_supplicant: Device is trying to offload WPS Probe Response while not supporting this
Feb 18 16:25:38 iothub1 wpa_supplicant: Device is trying to offload WPS Probe Response while not supporting this
Feb 18 16:25:38 iothub1 wpa_supplicant: wlan0: AP-STA-CONNECTED 78:45:61:ee:43:47
Feb 18 16:25:38 iothub1 kernel: [ 1726.789198] ieee80211 phy0: vif 0: set_key cmd 0
Feb 18 16:25:38 iothub1 kernel: [ 1726.789213] ieee80211 phy0: CCMP_PAIRWISE keylen=16!
Feb 18 16:25:38 iothub1 dnsmasq-dhcp: DHCPREQUEST(wlan0) 10.42.0.153 78:45:61:ee:43:47
Feb 18 16:25:38 iothub1 dnsmasq-dhcp: DHCPACK(wlan0) 10.42.0.153 78:45:61:ee:43:47 ideapad
Feb 18 16:26:07 iothub1 kernel: [ 1755.102706] sunxi-mmc 1c10000.mmc: smc 1 err, cmd 53, RD DCE !!
Feb 18 16:26:07 iothub1 kernel: [ 1755.109460] sunxi-mmc 1c10000.mmc: data error, sending stop command
Just a note, on modern installations you don't ever manually configure the /etc/resolv.conf it is automatically maintained by other services. Plain openvpn installation don't do dns push lines unless you tweak them from the server side, the network manager plugin which is part of the gnome packages does this automatically while restarting whole networking.
We have some amazon to datacenter bridges and even my soc installations are connected to datacenter network services by openvpn client. Most of the problems started when ubuntu started using network manager on desktop images but dns push routes took a lot off man hours to get them right. Currenlty I add manually the hostnames and don't rely on dns lookups.
p.s) Raspbian is based on Debian Jessie. They just don't follow the normal debian development and manually merge the security patches (when ever feel like it, so not often).
Therefore basic Debian guides will work unless we are talking something on lower level arm support etch.