best performance files alignment between two nodes

[Enrico Venturi]

Hello colleagues.
I work in the high availability systems area.
We want to design an active-standby mechanism where the standby node is periodically updated with the relevant data files stored in the active node.
Taking into account that only the changed files should be copied, and some files can be slightly changed even if its size is very big, can you suggest to me a tool or a mechanism to realize a low cost - high performances data alignment?
Thank you in advance
Enrico

[Bill McNAMARA_1]

Did you try service guard?

Problem with doing mirror on remote mounts via scripts is that there may be corruption and a lot of syncing to be done on switch over..

I think you need to push for tru64's clustered filesystem to be integrated.. I believe it's due some time next year..

Later,
Bill

[Enrico Venturi]

mmmhhh, I forgot to write that we already use MC/SG (since 1998) just for "local redundancy"; now we want a "geographical redundancy" mechanism ... something protecting against disasters on a building / campus/ town ...
Anyway thanks Bill!

[A. Clay Stephenson]

THe best answer is something like EMC's SRDF links or ESCON links so that data is synced 'behind the scenes' but since you mentioned low-cost you can forget those options. If this is Oracle data, you might consider a standby database.

The only other scheme that I can suggest is that you compute a checksum for every block of a file and store those block number, cksum tuples in some sort of database (which might simply be a file). You then have a daemon which reads the data files and computes new checksums. If those checksums differ from the original values or if new blocks have been added to the data then those blocks are sent and the checksum database is updated with the new values.

[Charles McCary]

Enrico,

what type of data? The reason I ask is that Oracle has a replication facility.

tx,
c

[Enrico Venturi]

Flat files.

[harry d brown jr]

You have about 60 posts that you haven't responded to:
http://forums.itrc.hp.com/cm/TopSolutions/1,,BR62571!1!questions,00.html

live free or die
harry

[Enrico Venturi]

Mr. Brown,
sorry but I couldn't understand the meaning of your reply: what have I to do in your mind?

regards
Enrico