Re: mkisofs memory hungry?

[scdbackup@gmx.net]

Hi,

> DVD backup server. This machine has 96MB memory,

That machine must be several years older than the
DVD burner.


> I thought mkisofs is somewhat pipeline process, files comes in, iso
> images goes out. I thought the memory needed is not directly related to
> the amount of data to make ISO image,

My experience is that memory consumption of mkisofs 
depends mainly on the number of files. 

A consumption of 50 to 100 MB for a 4 GB ISO image is
not unusual. That's single percent of payload.
Since you got many small files, the ratio might be higher.

I got a subtree of 2 million empty files where mkisofs
exceeds 2 GB of memory consumption. I never found out
wether it would finally end or crash.


> Thanks for suggestions and ideas in advance.

You could abandon the concept to record all your files
directly in an ISO image and rather employ some archive
format.

You may burn archives from afio or star without an ISO
wrapper. Both programs are smart enough to unpack from
media which do not deliver a clean end-of-tape.
Like
   find . | afio -ovZ - | growisofs -Z /dev/hdc=/dev/fd/0
To be read from unmounted media like
   afio -ivZ  /dev/dvd

This is what i use for system backup in single user mode:
   star -c -xdev -acl -link-dirs level=0 -C /mnt . \
    | gzip | growisofs -Z /dev/hdc=/dev/fd/0
To be read by
   gunzip </dev/dvd | star -x -v


Then there is
    http://www.serice.net/shunt/
which produces ISO images with a series of tar archives
on-the-fly. (Look for "flyisofs")


Have a nice day :)

Thomas