--- Nilesh Chaudhari listbox@nilesh.net wrote:
Animesh Singh wrote:
There should be little to no data loss in soultion.
zero data loss = 'synchronous' solution. anything other than this is async - where ur data loss is unpredictable - can be zero to any number of I/Os.
...
What will be the best way to have Disaster Recovery of site ( File & Print and Messaging Soluton.
). at
remote location with approx. 300 km. distance. & with 2Mbps link.
one 2 Mbps IP link can transfer 2 x 0.8 x 1000 / 8 = 200 Kilobytes of data per second.(0.8 becoz 20% of IP overheads). That means your data at primary should have a change rate much less than this if you want synchronous replication.
There can never be `no data loss'. Some data is always lost in such incidents where a whole site goes down.
Not true. You can have zero data loss solutions - problem is...they need humungous bandwidth and/or they screw up your application response times.
You have these options for Linux/*nix -
- journalling file system
- tar, gunzip
- dd, cp
- fsck
- taper, cdrw-taper
- linux single
- http://linux-ha.org/
- http://www.linuxvirtualserver.org/
- and so on...
none of these will work. you need to use proprietary solutions that will intercept Write calls to the OS, transfer them to DR site, actually write to remote disk, get an acknowledge from there, write to local disk, and *only then* acknowledge a successful write to applcation.(now u know why zero data loss solutions cost a bomb and screw up app response times)
kishor
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