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Journaling Filesystems and Network Mirroring?
CustomDesigned asks: "We are looking at the feasibility of mirroring all changes to selected filesystems to a hot backup over an internet or WAN link.
This would provide a degree of protection for a business in the wake
of a disaster like Sep 11. It seems that journaling filesystems have
much of the work already done. All that is needed is a hook to copy
log data into a message queueing system for delivery to the hot
backup, and then running fsck for the unmounted file system to apply
each log update. (This is more complex for ext3 where the log data
is kept internally within the filesystem.) One problem is that JFS
(and I presume ext3) only journal filesystem metadata. Has anyone
seen a fully journaling filesystem? Is there any other work on remote
hot backups for Linux? The toolset for any such capability should
include a way to measure bandwidth required for a given filesystem
without actually doing it. This would allow intelligent
administrative decisions to balance bandwidth costs against
traditional removable media backups."
According to this document, ext3 supports three different journalling modes, including one where all data is written to the journal, rather than just the metadata.
In the world of stock prices not in danger of being delisted, Some investors, like the ones who invest in my company, may not like the idea that you're mirroring your critical data with a relatively new, and "unheard of" filesystem. Be very careful. Remember, in this economy it's not about what you believe in; its what your investors want you to believe in. The political metalayer of the OSI model has become the most important. Then again, your data may not consist of customers financial data in bulk quantities. YMMV.
If politics and such are important in your company, Look into "real" technologies such as EMC (Sym or Clariion), Hitachi, or IBM storage, even if you have no real intention of buying. Make a brief outline as to why these systems would not be cost-effective, or fit your needs, just so your investors will know you put some thought into it.
I'm not trying to troll, i'm just offering information you may want to consider. Again, YMMV
Just my unsolicited $0.02