Why is the live usb experience so bad?

**Background Context (you can skip this if you want): **

Every time I buy a new laptop, I like to try a new linux distro for a while to see if the grass is greener on the other side or simply if I am missing something. I start out by creating a live usb of the distro to see how things work in general, and use it that way for personal stuff like surfing and etc. If I like what I see, I then install it onto the drive and start using it for actual use for new projects. If I like the distro more than my previous one I switch, if not I remove it and go back to what I had before.

The Problem:

So I made a live usb of Leap 15.2 KDE and tested it, and lets just say it was laggy as hell and kept freezing up. I had no problems running other distros via the usb drive, linux mint, kubuntu, kde neon and etc via usb.

If I were to off the top of my head guess what the problem is, that would be that the OS is constantly being loaded from the USB (which in this case is a USB 2.0 drive) instead of loading itself in a ramdisk and maybe only making the home folder persistent or disable persistence to begin with.

I went to see if I could customize the livecd via the suse studio but that now seems to be dead. Replacing with a more complex tool with no straightforward option for making livecds anymore.

Now sure, I can probably look into these problems and debug it. But that’s not a very good user experience for most people simply trying to test a distro. Most people would just do what I did, try something ubuntu and go with that as it feels much smoother.

I am not trying to bash opensuse here, this time I opted for KDE Neon, but next time I get a new laptop, I wish to again try opensuse and see how it goes. And hoping by then the liveusb experience will be more normal (without me having to opt for the fastest USB4 drive).

Of course it is also possible that there was some driver issue, albeit again I ran a few linux distros already on it with no issue.

Seems to be your problem. Tried openSUSE Tumbleweed and Leap on many occasions and never encountered problems related specifically to openSUSE: How To Try openSUSE Without Making Any Changes To Your PC - openSUSE Wiki

Using USB 2.0 the initial boot may be quite slow, especially if the usb drive is large, as it is not until first boot that remaining free space is allocated to the persistent file system.

Subsequent boots are much faster and the system should be usable for evaluation purposes. Ideally though you want to use USB 3, the difference is quite noticeable, also of course, speed depends upon the USB device you’re using.

You can run without using persistence, which will speed things up quite a lot in general, although if you want to retain any changes made then that obviously isn’t an option.



to the command line at boot.

I think it is quite difficult to reliably compare the performance of live distros: The hardware environment deployed (i.e. computer and USB-device) needs to be identical for all distros, the desktop environment of the distros should be the same, etc.

The USB-Device might be the weakest link in the chain: USB-devices of the same technology can differ in data-transfer-speed even if they come from the same vendor. Not to mention all those low quality products with faked size and speed parameters. And USB2 offers much lower data-transfer-rates than USB3.

However i can confirm that openSUSE Leap or Tumbleweed with KDE desktop environment put on a standard quality USB2 memory stick will not perform very well. If only USB2 is available and one wants to use an openSUSE Live KDE system on a daily bases i would recommend the use of an USB2 hard disk drive.

Personally i use an openSUSE Tumbleweed system with KDE desktop (as rescue system) on an USB3 32GB memory stick (from a well-known vendor) and it shows a good performs (when used on USB3 ports of a desktop or a laptop).



Even USB 3.0 is a big bottleneck during system startup. While host 3400G spends 1.5 seconds in userspace for reaching graphical.target it takes 14 seconds when booting from a fast stick:

Model Family:     SanDisk based SSDs
**Device Model:     SanDisk SSD U100 64GB**
LU WWN Device Id: 5 001b44 0fa44e1fa
Firmware Version: KM.10.00
User Capacity:    64,023,257,088 bytes [64.0 GB]
Sector Size:      512 bytes logical/physical
Rotation Rate:    Solid State Device
Form Factor:      1.8 inches
Device is:        In smartctl database [for details use: -P show]
ATA Version is:   ACS-2 T13/2015-D revision 3
SATA Version is:  SATA 3.0, 6.0 Gb/s (current: 3.0 Gb/s)

However with all files used by the running applications being buffered in RAM users can’t tell anymore the difference between Leap 15.2 running from SATA 3.0, 6.0 Gb/s SSD and SATA 3.0 3.0 Gb/s USB Stick. The live system readily updated by reinstalling some 350 packages without further ado in some 15 minutes.

Operating System: openSUSE Leap 15.2
KDE Plasma Version: 5.18.6
KDE Frameworks Version: 5.71.0
Qt Version: 5.12.7
Kernel Version: 5.3.18-lp152.33-default
OS Type: 64-bit
Processors: 8 × AMD Ryzen 5 3400G with Radeon Vega Graphics
Memory: 29,3 GiB

Memory usage is moderate:

linux:~ # free -h
              total        used        free      shared  buff/cache   available
Mem:           29Gi       1.3Gi        25Gi       201Mi       2.3Gi        27Gi
Swap:            0B          0B          0B
linux:~ # 

Load averages are higher than when booted from SSD:

linux:~ # w
 14:03:50 up 38 min,  3 users,  load average: 0.18, 0.21, 0.25
USER     TTY      FROM             LOGIN@   IDLE   JCPU   PCPU WHAT
linux    tty7     :0               13:25   38:28  37.54s  0.03s /usr/bin/startplasma-x11
linux    pts/0    :0               13:25   37:51   0.00s  1.32s kded5
linux    pts/1    :0               13:26    4.00s  0.21s  0.03s /bin/bash
linux:~ #