Hi Jennifer,
Did you call nc_set_chunk_cache? If not, do you know what the default cache
size was set up to? (Look in your config.log created after you called
configure)
I must admit that 20 seconds is quite long.
Denis
From: netcdfgroup-bounces@xxxxxxxxxxxxxxxx
[mailto:netcdfgroup-bounces@xxxxxxxxxxxxxxxx] On Behalf Of Jennifer Adams
Sent: Thursday, September 09, 2010 7:34 PM
To: netCDF Mail List
Subject: [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
