I could not find a solution for creating a Fedora Live USB drive with persistence. My objective is to have a ‘rescue disk’ with extra software installed which would persist through boots.
So I took two identical 64GB USB drives. The first I installed Fedora Live. I then booted to that drive and installed Fedora on the other drive.
When I boot to the second drive with Fedora installed, the results are horrible. Installed Fedora runs orders of magnitude slower than Fedora Live.
What am I missing here? Both drives are the same speed, yet there is such a drastic performance difference.
If I understand this correctly, You installed Fedora on one, and kept the second one as a LiveUSB. If I am not mistaken, the LiveUSB pushes things into RAM for the use case of running in the Live Environment.
The Installed is using the USB’s cache (if any. . . ) and also R/W & I/O which depending on the hardware you have could be running into contention or a lack of bandwidth.
For example on older intel Machines the DMI would throttle with a certain amount of USB drives/peripherals connected as the I?O was funneled through it. The “best” experience was using a HDD drive (good cache) with Enclosure to get the most out of the External Drive.
Also note. . . USB3 can top out at around 500Mb/s for SSD’s but only 200MB/s for HDD’s not accounting for contention for bandwidth. . . Results will vary.
USB4/Thunderbolt is much higher, but again. . . cache etc. . .
It is, As a matter of fact, I used to do this when I started using Fedora years ago. I also had 2 drives, 1 for Forensic/Repair tools and One just as a Live Environment.
The fact is, We know so little about how some of these drives perform as opposed to knowing they work under a certain spec. USB3 means nothing if the drive cannot output it’s potential ( an example I set above earlier ) I have cheap USB drives ( 32/64/128GB ), and I have “chuck” HDD’s and some “chuck” SSD’s. The External drives consistently outperform these “branded” USB3 drives due to cache.
If you need to run this setup, I suggest purchasing a used SSD/HDD and having it in an external enclosure and do what you like !
I am an expert in this field ! (pictured are 2x 8TB HDD’s, HGST/WD both over 128MB cache)
Also, the biggest upgrade for this usecase, was going away from Intel. AMD has an I/O die to negotiate this bandwidth over PCIe on the MoBo’s since Ryzen came out. Intel still uses DMI. . . Funneling that traffic.
You can mitigate this, if you know your USB drives cache (older HDD’s are good above 64MB, SSD’s very good above ~512MB)
Note for fun : Test the USB drives in variouos ways. A clear sign of a good performer is if you move a file larger than 4/8GB to it, If you start out “High” example +100MB/s and stay on that for the duration, you are good ! But if it tanks down to say ~50MB/s . . .No good for a Full Fedora install.
