Live system with overlay

bwh1969 · 2009-05-02 18:49:55

I am having an issue with session saving: the machine seems to shut down while the disk is still being written to and the overlay.ovl and mods.sqf are not being saved or ar only partially saved. This just started happening so I transferred the files to another disk and it is still recurring, so then I formatted the disk to ext3 rather than fat32, then transferred the system files back to the disk (larch, boot, system.sqf, mods.sqf, overlay.ovl, etc)

Still having the issue. The light on the usb drive is still going like mad when the system powers off.

Is there a script file somewhere that I can modify to have it delay the shutdown for a few moments?

I could also just use a squashfs command on the running system @ /.livesys/mods directory but I don't know what to use for the overlay directory... lzop? i could then just transfer the files back to the boot drive using another machine. I have a lot of mods and don't want to "start over."

gradgrind · 2009-05-03 10:31:29

That's very annoying!

I'm afraid my job is taking up a lot of time at the moment, so I can't work on larch much. There are a few fixes/updates that need doing, but I've no idea when I'll get round to it. However this is the first time I've heard this problem.

It would be most interesting to know what is causing it - is there some reason why the save and remount is completing before the actual operation is finished? Why has it suddenly started doing this?

Anyway, a delay should be no problem, you can put it in /etc/rc.shutdown, just before the line '#Power off or reboot'.

Another point that you should be aware of - the session merging option (rebuilding mods.sqf) will no longer work with kernel 2.6.29, as the feature of aufs it relies upon has been dropped in the new version of aufs. This is a bit of a pain, so I'll have to think of some sort of alternative approach ... sometime. (See my post on the larch thread: http://bbs.archlinux.org/viewtopic.php? … 18#p537718.)

bwh1969 · 2009-05-03 13:58:02

Then I won't be upgrading to a new distribution anytime soon. I used "Chakra Live" alpha one (still on my desktop machine) and it uses a faster version of squashfs. The kernel used for alpha2 (on my laptop machine with a similar 1.6 GHz processor) says "lzmatic" after the "building little endian system" before the progress bar approaches. It takes at least twice as long (conservative, I think it is many times slower) for it to build the mods overlay. It might save some space, (is it using lzop on the filesystem before putting it into the squashfs?), but at the expense of a lot of time.

I did figure out what to do: in /opt/larch-live/session-save. I added "sleep 10" right before the last 'exit 0' The 10 second pause seems to give the drive enough time to finish writing before it executes the shutdown.

I was used to FaunOS and changing that file to either save the whole overlay or just home, so I just started looking for a similar file.

It is a shame they are dropping the support for this method of saving. The OS clearly uses about half the space on a drive and is MUCH faster running in this manner. Side benefits:

Backing up a system is as simple as copying the mods.sqf and overlay.ovl to another device
Runs much faster, uses ramdisk and also the squash files tend not to be fragmented so on a disk, seek time seems faster.
In operating mode, the root filesystem is unchanged so if some sort of data corruption, maligned changed to the system, or package install failure, going back to the previous state is just a matter of rebooting.

The only downside I see is the time it takes to save a session. I never use just the "save overlay" option because it eats up the ramdisk on the next boot.

Last edited by bwh1969 (2009-05-03 13:58:19)

gradgrind · 2009-05-04 06:01:51

Thanks for the feedback.

Arch Linux

#1 2009-05-02 18:49:55

Live system with overlay

#2 2009-05-03 10:31:29

Re: Live system with overlay

#3 2009-05-03 13:58:02

Re: Live system with overlay

#4 2009-05-04 06:01:51

Re: Live system with overlay

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