Using a Read-Only Persistence Capability in Knoppix LiveUSBs

[Werner P. Schulz]

Caution! The size of '/tmp' is limited to 2 GB. I have had trouble with my script to remaster Knoppix. When I did CD remaster, all went well. But it takes a while to find the error when I did DVD remaster using '/tmp'-

[utu]

Thanks for the warning, Werner.

I was expecting the limit was 4 Gb, but I seem to remember there IS some
uncertainty as to whether 2 Gb or 4 Gb is the limit. You've apparently
'been there, done that'. If I understand you correctly, if I have a
KNOPPIXn that is compressed to 2 Gb or more it will cause trouble
expanding it on /tmp. Is that any different than expanding it to /?
I'm assuming 2.5:1 compression here.

I would have expected I might be able to
conjure up a KNOPPIX-DATA of about 10 Gb and store that as 4 Gb cloop
compressed on /mnt-system and sometime or other expand it again to
10 Gb on /. All this assuming no file in KNOPPIX-DATA ever exceeds 4 Gb.

Since my overlays are always incremental, small additions, I don't think
this is a problem if I am limited to 5 Gb in reiser terms and compressed
to 2 Gb on Fat32 on /mnt-system, but I can see this would be a problem
for re-mastering.

My understanding is that the limit is not a Fat32 limit per se, but
rather a limit of iso9660 filesize ON fat32 filesystems.

[Werner P. Schulz]

"df -h" shows the size of tmpfs mounted at '/tmp' is 2 GB. I've had the trouble while building new ISO of DVD at the point

genisoimage  ...  | create_compressed_fs  ....  -f /tmp  ...

The uncompressed size of Knoppix CD is about 1.9 GB and compressed about 0.8 GB and it fits within '/tmp'. The uncompressed size of DVD is about 9 GB and compressed it exceeds for me the size of 4 GB and that didn't work. Now I use the option "-f /opt/knx/knoppix_tmp".

The other problem while remaster Knoppix DVD: If I don't purge many big packages within DVD, I also cannot remaster a DVD, because the size limit for the new '/KNOPPIX/KNOPPIX' is 4 GB.

[utu]

If I don't purge many big packages within DVD, I also cannot remaster a DVD, because the size limit for the new '/KNOPPIX/KNOPPIX' is 4 GB.

Can't you break up the re-master into 4 Gb chunks?
Isn't that how the Knoppix DVD is constructed?
Doesn't it have KNOPPIX and KNOPPIX1 in /mnt-system/KNOPPIX/ ?
And can't you add KNOPPIX2, KNOPPIX3, etc ?

Also thanks for the clarification. I thought the KNOPPIX, KNOPPIX1, etc were
limited to 4 Gb not 2 Gb, and didn't know where the 2 Gb limit came in.
For my purposes, I don't need to play games with anything larger than 2 Gb on /tmp.
I only use that to test out the syntax of some of my small backup programs.

[utu]

I had already set up by default to move cromium cache, ~/.thumbnails, proxy cache to ramdisk.

This also interesting.
I had been establishing or re-establishing a reiserfs r/w persistence.
An alternative might be to use the ramdisk as a temporary r/w (in ram) for
some functions like *[Cc]ache* files.
I assume if I use the cheatcode noimage and forget my reiserfs that sets this up.
Not sure how to go about the re-routing of caches, however.

[Blacksimon]

To move cromium cache in ramdisk you have to use

/usr/bin/chromium %U --disk-cache-dir="/ramdisk"

right click on Menu/Internet/Browser web Chromium to change property or modify the Exec line in /home/knoppix/.local/share/application/Browser web Chromium.desktop file

To move ~/.thumbnails in ramdisk you have to add in /etc/init.d/knoppix-autoconfig at line 739 (function start_fs) this code

[ -d /home/knoppix/.thumbnails ]  || mkdir /home/knoppix/.thumbnails
mount -t tmpfs -o rw,size=200M,suid,dev tmpfs /home/knoppix/.thumbnails

I think you can use even other directory

[utu]

To move cromium cache in ramdisk you have to use...

The chromium cache is already in ramdisk, operating without persistence. See

updatedb; locate *[Cc]ache* | grep chromium

after booting with noimage and no prior re-arrangement of the cache.
This cache's current contents are probably lost on re-boot of course.

[Blacksimon]

sure with noimage code and KNOPPIX1 always is in ramdisk
post #16 was intended for normal r/w persistence which motivated the exclusion of cache in mkisofs in post #9

[utu]

@Blacksimon
My concern is that you _may_ have allotted chromium cache space in two places in ramdisk.
If your intention is to end up with one chromium cache, I don't think you need to go through
the extra effort you have provided. I think the cache just moves from r/w to ramdisk with no extra effort
on your part. The exclude is still useful to minimize the what's in KNOPPIX1.

[Capricorny]

'~/.gvfs' isn't a ordinary file; it is the mountpoint for GVFS. Therefore you cannot delete or copy it.

http://en.wikipedia.org/wiki/GVFS

All my self-created mount points can be deleted when not in use. And nothing seems to be mounted on my .gvfs, still there is no way to modify it using the ordinary file system commands. So .gvfs is something else, to me seemingly introducing new system features in userspace.

Maybe no wonder Miguel de Icaza is now a dedicated Mac user...?