[Q] Dbexport and file space?

I am UNIX system admin and I don't know anything about Informix, but I have very strong ORACLE DBA experienced. Today, I argue with our INFORMIX DBA. He ask me allocate at least 4GB free space for him to do the "dbexport. His reason base on Informix database already take 4GB chunk. Base on my ORACLE experience, export database take less space than actual database take. I mention to Informix DBA, when FIRST time new project doing export, we always need "try and error" several times to figure out how many space we need. He refuse to do that and ask me allocate large space for him. My question are: 1. how can we estimate how big space need for dbexport? 2. is it possible we can compress files while dbexport (for example on ORACLE we can "exp file= aaa ...|compress)? Thanks you for help.

You're both right. The export will take less space than the 4GBytes of space the database uses, for the same reason as in oracle, ie it's just the raw data, no idexes etc. But it's not easy to estimate how much it will take. In my experience, ususally about one third of the space used in Informix, but of course this depends upon all sorts of factors. So, if were me, I'd allocate the 4GBytes requested. Once the export's finished, you can use bdf to see how much was exactly used. And, by extrapolation, you'll know next time. 4GBytes seems, these days, to be a negligible amount to be arguing about. Neil Truby Londis Stores Hampton Hill, UK L wrote in message ... >I am UNIX system admin and I don't know anything about Informix, >but I have very strong ORACLE DBA experienced. Today, I argue >with our INFORMIX DBA. He ask me allocate at least 4GB free space for him >to do the "dbexport. His reason base on Informix database already >take 4GB chunk. Base on my ORACLE experience, export database take >less space than actual database take. I mention to Informix DBA, >when FIRST time new project doing export, we always need "try and >error" several times to figure out how many space we need. He >refuse to do that and ask me allocate large space for him. My >question are: > > 1. how can we estimate how big space need for dbexport? > > 2. is it possible we can compress files while dbexport > (for example on ORACLE we can "exp file= aaa ...|compress)? > >Thanks you for help.

I've acually seen the dbexport process take more space than the database in it's native format. Remember, you get those delimiter characters between each field and numerics taking small amounts of space (ie. 2 or 4 bytes) can take up a lot of space in their ascii representation.