Due to the current gap in continued funding from the U.S. National Science Foundation (NSF), the NSF Unidata Program Center has temporarily paused most operations. See NSF Unidata Pause in Most Operations for details.

[netcdfgroup] nc_open takes a long time to open a big file

Dear Experts,
I'm using netcdf-4.1.1-rc1 and hdf5-1.8.4-patch1 on a 64-bit linux server running CentOS-5.5.
I have a netcdf-4 file that is 18404502496 bytes large.

My file's dimensions look like this:
        lon = 320 ;
        lat = 160 ;
        lev = 11 ;
        time = 1581 ;

It has 7 variables that look like this:
   float temp(time, lev, lat, lon) ;
                temp:_Storage = "chunked" ;
                temp:_ChunkSizes = 1, 1, 160, 320 ;
                temp:_DeflateLevel = 1 ;
                temp:_Shuffle = "true" ;

and 1 variable that looks like this:
    float sfp(time, lat, lon) ;
                sfp:_Storage = "chunked" ;
                sfp:_ChunkSizes = 1, 160, 320 ;
                sfp:_DeflateLevel = 1 ;
                sfp:_Shuffle = "true" ;

Is it normal for nc_open to take 20 seconds to open this file before returning control to my C program?

--Jennifer


--
Jennifer M. Adams
IGES/COLA
4041 Powder Mill Road, Suite 302
Calverton, MD 20705
jma@xxxxxxxxxxxxx



  • 2010 messages navigation, sorted by:
    1. Thread
    2. Subject
    3. Author
    4. Date
    5. ↑ Table Of Contents
  • Search the netcdfgroup archives: