Rescue Disk

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.

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You’re method with 2 USB disks is correct.

Is the rescue USB disk USB-3 and plugged into a USB-3 socket?

If either is USB-2 it will be very slow.

I have the same setup for me rescue disk.
I use Samsung usb ssd not a usb stick and its fast on USB-3.

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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. . .

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Drives are USB 3.0 in a USB 3.2 port. External SSD cost is prohibitive.

Since posting, I found some threads which also suggest that Live runs in RAM. That would easily explain the performance gap.

Guess this just isn’t possible…

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.

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Added clonezilla, file-recovery, live-usb, livecd, rescue

You may need to create a GPT partition table on the USB first.

To solve a performance issue?

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Just an FYI. I found a solution that works for me.

If the USB drive is properly partitioned for persistence (which Rufus does for you), Debian Live gives you persistence out-of-the-box.

Now I can load any packages, scripts, etc. needed and they will persistence through boots.

The Standard Live has no GUI, which is fine for my purposes. Haven’t tried, but you could probably use one of the GUI flavors to a similar end.

Many thanks for all the helpful discussions…

Here’s what Rufus does for you:

Changes/ModernizeLiveMedia - Fedora Project Wiki