# Check RAM Usage Ubuntu

#### You:
how do i check how much ram and what is using it on ubuntu

#### ChatGPT:
On Ubuntu, you can check both **how much RAM you have** and **what is using it** from the terminal.

### See overall RAM usage

```bash
free -h
```

Example output:

```text
               total        used        free      shared  buff/cache   available
Mem:            15Gi       5.2Gi       3.1Gi       200Mi       6.7Gi        9Gi
Swap:           2.0Gi         0B       2.0Gi
```

Key columns:

- **total**: installed RAM
- **used**: RAM currently in use
- **free**: completely unused RAM
- **available**: RAM available for new applications (often the most useful number)

---

### See memory usage by process

#### Option 1: `top`

```bash
top
```

Then press:

```text
M
```

(capital M) to sort by memory usage.

---

#### Option 2: `htop` (easier to read)

Install if needed:

```bash
sudo apt install htop
```

Run:

```bash
htop
```

Then:

- Press **F6** and select **MEM%**
- Or click the **MEM%** column if using a mouse

---

### Show the top memory-consuming processes

```bash
ps aux --sort=-%mem | head -20
```

This lists the 20 processes using the most RAM.

For a more readable format:

```bash
ps -eo pid,user,%mem,rss,comm --sort=-rss | head -20
```

Where:

- **PID** = process ID
- **RSS** = RAM used (in KB)
- **COMM** = command name

---

### See memory usage per program (interactive)

```bash
sudo apt install btop
btop
```

`btop` provides a modern interface with:

- RAM usage
- CPU usage
- Process list
- Network and disk activity

Many Ubuntu users find it easier to interpret than `top`.

---

### Check total installed RAM

```bash
grep MemTotal /proc/meminfo
```

or

```bash
sudo dmidecode -t memory
```

The second command also shows RAM stick sizes and slots.

---

### One-line summary

If you just want a quick answer:

```bash
free -h && ps aux --sort=-%mem | head
```

This shows total memory usage and the biggest RAM consumers in a single command.


#### You:
what
Last login: Tue May 26 16:57:34 2026 from 91.92.42.44
free -h
root@apollo:~# free -h
               total        used        free      shared  buff/cache   available
Mem:            15Gi       3.1Gi       438Mi       1.1Mi        12Gi        12Gi
Swap:             0B          0B          0B
root@apollo:~#

#### ChatGPT:
That output is actually quite healthy.

```text
Mem:
total        15Gi
used        3.1Gi
free        438Mi
buff/cache   12Gi
available    12Gi
```

What it means:

- **15 GiB total RAM** installed.
- **3.1 GiB actively used** by programs.
- **12 GiB in buff/cache**: Linux uses otherwise idle RAM to cache files and disk data to improve performance.
- **12 GiB available**: this is the important number. It means about 12 GiB can be given to applications immediately if needed.

The **438 MiB free** is not a problem. Linux intentionally keeps "free" RAM low because unused RAM is wasted RAM. It prefers to use spare memory as cache and release it when applications need it.

You currently have:

- \~3.1 GiB actually in use
- \~12 GiB available
- No swap configured

If you want to see *what* is using the 3.1 GiB, run:

```bash
ps -eo pid,user,%mem,rss,comm --sort=-rss | head -20
```

or install and run:

```bash
apt update
apt install htop
htop
```

Paste the output of the `ps` command and I can help identify which processes are consuming the memory.


#### You:
my backend vps says Resource Usage 95% ram usedf

#### ChatGPT:
If your VPS provider's dashboard says **95% RAM used**, while `free -h` shows:

```text
total       15Gi
used       3.1Gi
available  12Gi
```

then one of these is likely happening:

### 1. The provider counts Linux cache as "used RAM"

Many VPS dashboards calculate:

```text
used = total - free
```

Using your numbers:

```text
15 GiB - 438 MiB ≈ 14.6 GiB
```

That's about **97% usage**, which matches what the provider reports.

However, Linux considers most of that 12 GiB to be reclaimable cache, which is why `available` is still 12 GiB. In this case, your server is **not actually under memory pressure**.

### 2. The VPS dashboard is reporting cgroup/container memory

If you're running inside a container (Docker, LXC, OpenVZ, etc.), the provider may be measuring memory differently from what `free` reports.

Check:

```bash
cat /proc/meminfo | grep MemAvailable
```

and

```bash
cat /proc/1/cgroup
```

### 3. A process previously used memory and the dashboard is delayed

Some hosting panels update every few minutes and may not reflect the current state.

### Verify whether you're actually low on RAM

Run:

```bash
free -h
vmstat 1 5
```

and:

```bash
ps -eo pid,user,%mem,rss,comm --sort=-rss | head -15
```

Also check whether the kernel is killing processes due to memory pressure:

```bash
dmesg | grep -i oom
```

or:

```bash
journalctl -k | grep -i oom
```

### Quick interpretation of your current output

Based solely on:

```text
Mem: 15Gi total
Used: 3.1Gi
Available: 12Gi
```

your server appears to have **plenty of available memory** and is **not close to running out of RAM**. The provider's 95% figure is very likely counting cache as "used."

If you paste:

```bash
ps -eo pid,user,%mem,rss,comm --sort=-rss | head -15
```

and tell me the VPS provider (e.g., DigitalOcean, Hetzner, OVH, Contabo, etc.), I can explain exactly why their dashboard is showing 95%.
