On Thu, Mar 21, 2024 at 11:19:34AM -0400, Steve Petrie via talk wrote:
> Hello Lennart,
>
> Thank you for your speedy explanation that, probably the Debian live linux
> overlayfs mechanism is using a non-persistent tempfs ramdisk to store data
> written to the root filesystem.
>
> Your explanation could also explain why some Debian packages I install,
> disappear every time I boot my linux PC, which is often daily. So, I
> sometimes find myself occasionally re-installing a disappeared Debian
> package.
>
> * * *
> * * *
>
> I use a live Debian linux image booted from a USB memory stick, because the
> original Debian 9 linux installed on the 1.8 TB hard disk, was ruined when I
> ran a "fix broken packages" operation, on the advice of a web page, while I
> was trying to install some Debian package.
>
> This "fix" removed a zillion packages and left me with a minimal linux that
> would only boot to a command line.
>
> After struggling unsuccessfully to repair the broken Debian 9 on the 1.8 TB
> hard drive, I landed on the solution of booting Debian 11 live from a USB
> memory stick. (In an earlier post to GTALUG I described how I built the USB
> live boot stick from a Debian 11 CD image.)
>
> * * *
> * * *
>
> I would like to explore ways to change the writeable root ovwelay
> filesystem, from non-persistent tempfs ramdisk, to persistent hard disk
> storage.
>
> This would: (1) eliminate significant RAM consumption by the overlayfs, and
> (2) (presumably) eliminate the current nuisance of having Debian packages
> disappear, every time the linux PC is booted.
>
> According to the df -l report (below), it looks to me like the current
> tempfs ramdisk providing writeable root filesystem space, could occupy up to
> 7.8 GB of RAM.
>
> Right now the free command shows RAM in 1KB units:
> ...
> user@debian:~$ free
> total used free shared buff/cache
> available
> Mem: 16258232 1925004 10446368 1758144 3886860
> 12276760
> Swap: 0 0 0
> user@debian:~$
> ...
>
> So the linux PC has a total of 16 GB of RAM. Assuming my interpretation of
> the free command output is correct, the tempfs ramdisk is currently using
> ("shared") approximately 1.7 GB of RAM (about 10 percent of total RAM), but
> could (presumably) grow to consume up to 7.8 GB of RAM (per df command
> output). At 7.8 GB this would mean the tempfs ramdisk would consume almost
> 50 % of total RAM..
>
> My Debian live linux PC occasionally crashes, with the LED on the USB live
> stick flashing furiously, notably when I have many Firefox browser windows
> open. Maybe these crashes occur when the tempfs ramdisk gobbles up lots of
> RAM ??
>
> * * *
> * * *
>
> According to the df -l report (below), the 1.8 TB hard drive still has 958
> GB of free space available. So, moving the maximum 7.8 GB volatile tempfs
> overlay filesystem, from ramdisk to the 1.8 TB drive would consume only 0.81
> percent (7.8 / 958) of the available space on the 1.8 TB drive.
>
> Scary to move the tempfs overlay filesystem to a new partition on the 1.8 TB
> drive ??
>
> As I was trying to discover where the overlay filesystem is mapped, I read
> that some of the command line tools I was using, provide ways to
> RE-PARTITION disk drives.
>
> I am a VERY PARANOID ancient IT dude, who would NOT ENJOY doing some FINGERS
> CROSSED messing around with the partitioning on the 1.8 TB drive.
>
> Perhaps the stress-free way to move the overlay filesystem to (permanent)
> hard drive space, would be to add a second huge SATA hard drive to the linux
> PC ??
>
> * * *
> * * *
>
> Before buying another hard drive, I would research technical details of how
> to tell the Debian 11 live linux, to map the overlay filesystem to a
> partition on the new hard drive ??
>
> Naturally I will look into this question myself, but I would gratefully
> appreciate suggestions from GTALUG members :)
Well my understanding is that the Debian Live is only intended as a trial
system and optionally an installer. It is not meant to be persistent
at all.
Now having a quick look there is a page on the debian wiki with some
short instructions on how to add persistence to DebianLive.
https://live-team.pages.debian.net/live-manual/html/live-manual/customizing-run-time-behaviours.en.html
It seems to explain how one can make Debian live have persistent storage
on a USB key.
--
Len Sorensen
---
Post to this mailing list [email protected]
Unsubscribe from this mailing list https://gtalug.org/mailman/listinfo/talk
