Zaphod Beeblebrox wrote:
Actually, right back at you. You didn't fathom the meaning in my
statement. While your post was vague, I read the company's website to
I am sorry what was vague since I wrote 'continuous backup' in my post? The
whole idea is such a basic idea that if you put this to google you can get
wikipedia entry about it in first 3 results (I see in 2nd). Maybe you didnt know
anything about it makes it vague to you. The message I sent was quite clear and
plain.
determine the featureset they were claiming (although I missed their
postgres support --- I only read the "features" page). NetBSD's hammer
filesystem achieves replication at the filesystem layer (which will do
infinitely better at this problem than a block-only driver) by
maintaining a history of what's happened and being able to "select" (as
in the database term) changes to the filesystem that have occurred since
the last batch of blocks were shiped out to replication. This gives you
both fine grained recovery (basically changes to files are kept until
your "rules" define they should be freed) and replication and fine
grained recovery on the other side of replication. In fact, Hammer
delivers what they claim in a far more sophisticated way.
You might want to read this page too:
http://www.r1soft.com/CDP.html
(but it's NetBSD, not FreeBSD, unless someone decides to port it)
While Hammer might be doing a similar job, it is a filesystem not a backup
application and it wont replace backups. It doesnt just store the data in a
backup server. While eventually it might become a backup solution, it will take
years before that can happen. Even then, people will not just switch their
current filesystems overnight. The CDP backup softwares are available today, it
just needs a sort of driver to function in current system.
Also they support postgresql as well (while its usage is way smaller
than mysql)
http://www.r1soft.com/CDP_db_postgreSQL.html
In any case, the product guarantees that it can return your
databases to any point in the time. Do you see what you are missing? :)
Well... "I" am not missing it. I have that without making my filesystem
jump through an enormous hoop. But designing "my" application
correctly, I have that feature for far less effort. (that was the other
point of my post)
Can you just explain how can one currently do that in FreeBSD? Is it as easy as
in Linux with CDP backup softwares? such as installing a program and done?
I've spent a lot of time thinking about redundancy and I've come
to one inescapable conclusion: That the further up the stack you
design for redundancy, the cheaper and easier it becomes. Most
databases have replication strategies of one type or another
that don't require exotic hosting solutions to work.
The idea/problem is not redundancy here, it is data protection.
Well... no... you don't need fine grained filesystem history for data
integrity (unless you let loose a bunch of summer students armed with
the ability to RM or your application is faulty (in which case, your
filesystem won't protect you). As I said, This can all be achieved with
other far simpler solutions. However, if your dev team isn't smart
enough (or don't care for some reason), then you can take advantage of
their product and pay their price.
There is no perfect system. This is exactly why people take backups. If what you
said was applicable then there wouldnt be any need for backup software. People
would just make sure that they dont loose their data. In addition to this, I
have no control of if my customer will delete his/her data accidentally. I cant
make a system which does not allow customers to delete data.
I have given an example of a simple solution that Linux users can utilize (which
obviously we also can utilize if we put our heads into it and give some
directions as r1soft is willing to support FreeBSD). While you are first saying
that these can be achieved with far simpler solutions, at the same time you are
saying that the dev team must be smart enough.
My solution is simple enough to write here. You install Linux on all machines
and then CDP backup server on the backup server and CDP agent on the client
machines, is yours simpler? Then explain how we can create similar sort of data
protection?
Thanks,
Evren
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