SSH Troubleshooting Information

• This guide covers common SSH connection and performance issues on your Ultra.cc service, including login failures, temporary lockouts, high disk I/O, process-limit errors, and file-management questions.
• If you are looking for basic connection instructions, see the Connect to your Ultra slot via SSH guide first.

Connection Timed Out

• If your SSH connection times out after several failed login attempts, your IP may have been temporarily blocked from SSH login attempts.
• This is a soft ban and usually lasts 10 minutes.
• If this happens:
• Log in to the User Control Panel.
• Open your service.
• Go to the Connect tab.
• Click Change password beside SSH access.
• Set a new SSH/FTP password.
• Wait at least 10 minutes.
• Try logging in again with the new password.
• Do not keep trying to log in during the 10-minute wait. Attempting to log in again while the soft ban is active can refresh the ban and make you wait another 10 minutes.

Permission denied

• If you see a Permission denied error when connecting with SSH, check the following:
• Make sure you are using your correct Ultra username.
• Make sure you are using the correct hostname or IP address from the User Control Panel.
• Make sure the SSH port is set to 22.
• Make sure you are using your current SSH/FTP password.
• If you recently changed your password, update it in your SSH or SFTP client as well.
• Your SSH connection details are available in the Connect tab of the User Control Panel.
• Typical connection details are:

Hostname: <servername>.usbx.me or IP address
Username: <your-ultra-username>
Password: <your-ssh/ftp-password>
Port: 22

• You can also connect with OpenSSH using one of these formats:

ssh username@IP_of_slot
ssh username@servername.usbx.me
ssh username@username.servername.usbx.me

• If the details are correct but login still fails, reset your SSH/FTP password from the User Control Panel, wait a few minutes, and try again.

SSH or SFTP suddenly stopped accepting the correct password

• SSH and SFTP use your SSH/FTP password from the User Control Panel.
• If SSH or SFTP suddenly stops accepting a password that previously worked:
• Log in to the User Control Panel.
• Open your service.
• Go to the Connect tab.
• Click Change password beside SSH access.
• Set a new password.
• Update the saved password in your SSH or SFTP client.
• Try connecting again.
• This is also a useful first step after maintenance, migration, or other service-side changes.
• If the issue continues after changing your password, open a support ticket so the Ultra.cc team can review your service.

How to check high disk IO utilization?

• If your apps are slow or your slot feels sluggish, high disk I/O is one of the most common causes.
• Any file access on the disk creates I/O load on HDD-based services. This can be caused by your own activity or by other clients on the same disk. NVMe slots are less affected because of their much higher I/O throughput.
• Common causes of high disk I/O include:
• Torrent clients checking torrents
• Very active torrents
• Unpacking files
• Usenet downloading, repairing, or unpacking
• Constant Rclone operations
• Multiple FTP or SFTP streams
• Plex, Emby, or Jellyfin library scans
• Moving or deleting very large directories
• Multiple apps performing heavy work at the same time
• To check the I/O utilization of the disk your service is deployed on, connect to your service via SSH and run:

iostat -xk 2 $(findmnt -T ~ | awk 'END {print $2}')

• Watch the %util column.
• If %util stays near 100% for a prolonged time, the disk is saturated. This can affect app performance, file transfers, SSH responsiveness, and WebUI loading.

What to do if disk I/O is high

• If disk I/O is high, try reducing concurrent activity on your service:
• Limit the number of active torrent downloads.
• Pause or reduce torrent checking.
• Avoid unpacking while downloads are active.
• Reduce Usenet download, repair, or unpack concurrency.
• Pause large FTP/SFTP transfers.
• Reduce the number of parallel FTP/SFTP streams.
• Pause media library scans.
• Avoid running heavy Rclone operations during other disk-heavy activity.
• Use queueing features in your apps where available
• If the high I/O continues and your own processes do not appear to be responsible, another client on the same disk may be causing the issue. In that case, open a support ticket so the Ultra.cc team can investigate.

How to check disk I/O per process

• If you suspect one of your own apps or commands is causing high disk I/O, you can check individual process usage.

Option 1: Use htop

Run:

htop

• Look for the DISK R/W column. This column shows the disk read/write rate per process.
• Pay attention to the unit shown:
• B/s = bytes per second
• K/s = kilobytes per second
• M/s = megabytes per second
• If the DISK R/W column is not visible, enable it in htop:
• Press F2 to open Setup.
• Go to Columns.
• Move to Available Columns.
• Find IO_RATE.
• Press Enter to add it to Active Columns.
• Use F7 / F8 to move the column if needed.
• Press F10 to exit setup.
• You should now see the DISK R/W column.

Option 2: Use pidstat

• You can also use:

pidstat -dl 2

• This displays disk I/O activity per process at regular intervals.
• If you find a specific app or command causing heavy I/O, reduce its activity, stop it temporarily, or adjust its settings.

SSH error: Resource temporarily unavailable

• If SSH fails with an error such as:

Resource temporarily unavailable
OR
su: failed to execute /bin/bash: Resource temporarily unavailable
OR
shell request failed

• Your service may have reached its process or thread limit.
• Ultra.cc services have resource limits to ensure fair usage across shared servers. If an app or script creates too many processes or threads, new shells and app processes may fail to start.
• Common causes include:
• Rclone or Syncthing spawning many workers
• Cloud sync tools or tunnel services
• Custom scripts with too much concurrency
• Python, Java, or Node applications using too many threads
• Misconfigured plugins or background services
• Apps stuck in a crash loop
• If you cannot access SSH at all, or restarting apps does not resolve the issue, open a support ticket. Support can check the account state and identify which process is causing the issue.

How to clear up disk space or move data from my slot?

• The easiest way to manage any data is by using your favorite SFTP/FTP client. Filezilla is the most popular choice.
• We recommend using SFTP as your connection of choice because it is more flexible on which folders to manage. You can also drag and drop with an SFTP/FTP client, which makes it incredibly useful as a whole.
• The downside of this is that it takes time for the client to process your moves.
• See our 📘Connect to your Ultra slot with FTP guide for detailed instructions on how to connect to your service via FTPS/SFTP.
• However, the fastest way is by using SSH, but this might be intimidating for inexperienced users. For starters, you can use Midnight Commander, which is a graphical user interface file manager in your slot. It can be started by executing mc in your shell.

Some of my files have duplicates in ~/files or ~/downloads directory and ~/media directory. Are they using double disk space?

• If you're using Radarr/Sonarr/Sickchill/Medusa etc., they should not be taking any additional space.
• By default, these applications create a hardlink of the file to the default root directory of your application.
• A hard link can be described as a single file located at two different paths but pointing at the same block of data on the disk. Think of it as two signposts from other streets that direct you to the same destination.
• Hardlinks do not take any extra space. You can compare the inode numbers for both files from the Terminal (SSH Access) with ls -I on both files'. The inode number will be the same.
• You can read more about Hard Links here: https://en.wikipedia.org/wiki/Hardlink.

If you require further assistance, you can open a support ticket here!

• SSH Troubleshooting Information
• Connection Timed Out
• Permission denied
• SSH or SFTP suddenly stopped accepting the correct password
• How to check high disk IO utilization?
• What to do if disk I/O is high
• How to check disk I/O per process
• Option 1: Use htop
• Option 2: Use pidstat
• SSH error: Resource temporarily unavailable
• How to clear up disk space or move data from my slot?
• Some of my files have duplicates in ~/files or ~/downloads directory and ~/media directory. Are they using double disk space?