Re: I can't lose a single transaction, how 2 backup?

In article <361F1C13.6557@cyberramp.net>, Greg <greg@cyberramp.net> writes >Gilbert Gosseyn wrote: >> >> I set up a very important database and I wnat to protect myself against HD >> failure. Every day I make a level 0 backup and I start to perform backup of >> full logical logs. But what happen if my HD crash before the logical log >fills? >> All the transaction inside the last-not-filled logical log will be lost? >> Thank you in advance >> >> Leandro > >Leandro... > >You should be mirroring your disks at minimum. Then both disks of a >pair (primary and it's mirror, - *not* just any pair...) would have to >fail within a small time window to produce data loss. This is extremely >unlikely. Better yet, your disk array should have a "hot spare" to >replace any failed drive immediately, then it takes 3 specific disk >failures to produce data loss (primary + secondary + hot spare). Your >disk array should also have enough battery power on board to finish >commiting any writes and shut down gracefully on a power outage -5 >minutes minimum, or have ample UPS for the system to run >indefinitely. If that's not good enough, triple mirror (I know of >people who do this with >500GB databases...). If you are concerned >about nuclear attack, you may need to replicate across a wide area to a >hot site far, far away. > >OK - I'm getting a little silly but you get my point - you'll still have >decisions to make about how serious you are about "not losing a single >txn" and how much money you are willing to back up that assertion >with. Every additional layer of safety costs more and more. > >From the log backup standpoint, you should be doing continuous backup of >logs, to get them off to tape as soon as possible. Keep your logfiles >small so not much stuff is stuck in an un-backed up log, should >catastrophe strike (oops, I shoudn't have dropped that table...). > Don;t joke, someone I know once did a) unload table in demo database b) switch to live enviroment (same database name) c) drop table in LIVE database. Under Online 5 it took 3 goes at restoring (eject the tape at the right time as o PIT restore under 5.x). Still I got a free dinner from her for fixing it... >You'll find out how important the data *really* is when you ask for the >money to go do these things. That will be the most interesting >part.... Let us know how it goes.... > >Greg -- David Williams Maintainer of the Informix FAQ Primary site (Beta Version) http://www.smooth1.demon.co.uk Official site http://www.iiug.org/techinfo/faq/faq_top.html I see you standin', Standin' on your own, It's such a lonely place for you, For you to be If you need a shoulder, Or if you need a friend, I'll be here standing, Until the bitter end... So don't chastise me Or think I, I mean you harm... All I ever wanted Was for you To know that I care