[lug] writeable CD curiosity

D. Stimits stimits at comcast.net
Wed Feb 11 13:55:58 MST 2004

Thinking about firewalls that run on read-only media, but need logging 
ability, solid state ram devices seem ideal for reducing 
size/power/failure rate associated with devices that have fans (the 
typical PC used for firewalling/bridging). All of this of course made 
real by my current hard drive failure that was on /var/ partition.

So I am curious about limitations of current writeable CD hardware. 
Initial limitations of ISO9660 filesystems come to mind, but I'm not 
actually interested in ISO9660 filesystems. I am wondering what in the 
hardware would prevent a rewriteable CD from being used with ext2 or 
other "ordinary" random access filesystem? Performance would be 
incredibly bad, but for logs I wouldn't care anyway.

As a half-version of a fully rewriteable CD filesystem partition, I'd 
consider something from recent posts: ram-based partitions, which would 
occasionally append to a CD-RW or CD-R either when it reaches a certain 
capacity or when logs are rotated, e.g., log to ram, and then over time 
transfer from ram to CD-R or CD-RW; pop the logs out via ejecting the 
CD, and put a new one in, whenever the 650 MB or so of logs are reached. 
A full historical log record that can be browsed and analyzed.

Another possibility that I wonder about only for curiosity, and not 
necessarily for logging, is the concept of a RAID 1 where the partitions 
being mirrored are (a) a ram-based filesystem and (b) a rewriteable CD 
system...if power fails and ram is flushed, then the CD is used for 
rebuilding the array; or while power runs, the CD could be ejected and 
saved, a new CD added, and have it automatically rebuild the array via 
copy from ram to CD-RW. What are the hardware limitations to this?

D. Stimits, stimits AT comcast DOT net

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