Why is my headless Ubuntu server (20.04) terminal slow to display the command prompt after loggin in?

Micheal Saunders

4/2/23, 11:11 AM

I have a weird problem, I have a server running headless Ubuntu 20.04, and I have setup SSH access local only via PuTTY, but when I open PuTTY and connect to the server, and after I've entered the login details, as soon as I press enter to enter my password, it takes about 3-5 minutes for the command prompt to appear, simple command like clear, works fast, but when I upgrade by using apt get upgrade, normally it would be fast with the status bar at the bottom moving really fast, but recently (in the last week or so), that status bar has been moving really slow, and when apt starts fetching files for upgrading, the fetching is also very slow, but the downloads are vey fast, it seems there's a huge time delay between when apt fetches a file and when it unpacks it.

at one point when there was some upgrades, there was only some library files and PHP related files, around 15 files in total, it took 15 minutes for the status bar to finish and the command prompt returns, but if I were to reboot the server, everything runs really quickly, then somewhere within a week it slows down.

How can I tell what's causing the server to suddenly start crawling?

0 + 0

server

waltinator

4/2/23, 6:49 PM

Look at the logs! `sudo journalctl -b 0 -u NetworkManager`. Read `man journalctl`.

Micheal Saunders

4/4/23, 9:12 AM

I looked at the logs, and nothing was found unusual. I wanted to use a packet sniffer, but being that the server is using headless Ubuntu, wireshark is out of the question. Is there a CLI packet sniffer that can run continuously and record it's output to a text file, until I press CTRL-C or Q, much the same way as htop or top runs?

waltinator

4/5/23, 3:42 PM

Yes. Read `man tcpdump`. You can capture data in `.pcap` format on your headless server, transfer the `.pcap` file to a GUI system and load it into `wireshark`.

Micheal Saunders

4/6/23, 4:20 AM

Thanks, I found the problem using tcpdump, the network was bottlenecking during the transfer of backups from other workstations, for some reason, and I can't figure it out, the network, even though I'm using GiGaBit LAN throughout, was actually using 100MB, then dropping to 10MB when transferring large files.

Elon Musk

I sit in a Tesla and translated this thread with Ai:

EN: Why is my headless Ubuntu server (20.04) terminal slow to display the command prompt after loggin in?

TH: เหตุใดเซิร์ฟเวอร์ Ubuntu หัวขาด (20.04) ของฉันจึงแสดงพรอมต์คำสั่งช้าหลังจากเข้าสู่ระบบ

RO: De ce terminalul meu server Ubuntu fără cap (20.04) afișează lent promptul de comandă după conectare?

RU: Почему мой безголовый терминал сервера Ubuntu (20.04) медленно отображает командную строку после входа в систему?

VI: Tại sao thiết bị đầu cuối máy chủ Ubuntu không đầu (20.04) của tôi chậm hiển thị dấu nhắc lệnh sau khi đăng nhập?

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