This is a fresh install of Debian 8 (minimal, netinstall). The load average is constantly >1 with sluggish response times, long hang times on login, and so on. I'm really baffled about what could cause it. Disk IO, network IO, and CPU usage are minimal. Nonetheless, the load average does not reflect a freshly installed system and, as mentioned, everything is sluggish.

Ping average is 85ms.

I'm really at a loss as to what could make the system behave so sluggishly. In addition to being a fresh install, it's all new hardware. Any tips or advice on what to look for would be much appreciated.

benchmark htop, iotop

  • Try atop. It's more detailed. If you find nothing, try a live CD or two for different Linux distributions and check how things are running. If you figure it out, post an answer. Sounds interesting. – Ryan Babchishin Sep 23 '16 at 5:53
  • Hi, thanks for responding. When I run atop I see this: puu.sh/rkQit/e2b0793e64.png . I take it, then, it's a disk issue? – Beep13 Sep 23 '16 at 5:54
  • That is a very busy disk, it's possible. If the system is supposed to be idle, I'd look for the cause. The process list in atop (at the bottom) can show you what processes are using the most disk IO. I believe by default it puts those processes at the top of the list. Of course, a busy disk doesn't always slow a system too much or at all. I guess if it was your root partitions drive. It depends... – Ryan Babchishin Sep 23 '16 at 6:02
  • A little further investigation and use of 'mdadm --detail' shows that md0 is resyncing... for whatever reason. I guess I'll just let that finish and see if it improves. The system only has 2 disks, so they are the root partition drives. – Beep13 Sep 23 '16 at 6:09
  • mdadm will initialize any RAID array it creates if it detects existing filesystems metadata on them prior to creation. You can optionally not do this during creation, but only using the command line (rather than the Debian installer tool). – Spooler Sep 23 '16 at 6:16

For performance issues you can look to the different resources (Storage, Processing, Networking, etc.) to determine if one is causing the slowdown. Tools for this include htop, atop (as suggested by Ryan Babchishin in the comments), and ntop, among others.

Another thing to check is the drivers/hardware compatibility and functionality - as unsupported or malfunctioning hardware can cause a variety of problems (and can happen even on new hardware). An example would be using memtest86 to check your RAM, or checking the SMART status of your hard drives.

Based on your screenshot, and comment, it seems that your root drive is on an array which is re-synchronizing. This will lead to a slow system as things like writing logs and reading files (eg. /etc/passwd) are competing for I/O with the rebuild.

I have personally found this occurs on a machine I run, and once the rebuild/re-sync completes performance returns to normal. Please update your question if it does not.

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