Run FINCHFS

Run finchfsd

finchfsd starts with MPI. The finchfsd options are the following.

• -c db_dir : specifies a database directory or a DAX device. If the directory does not exist, it will be created.

• -v log_level : specifies the log level (e.g. debug). Default is info.

An example of a script is the following.

NUM_NODES=10
NUM_CLIENTS=$((NUM_NODES * 24)) # ppn is 24
FINCHFSD_PPN=8
export UCX_NUM_EPS=$NUM_CLIENTS
mpirun -np $((NUM_NODES*FINCHFSD_PPN)) -hostfile /path/to/hostfile --map-by ppr:$FINCHFSD_PPN:node:PE=1 -x UCX_NUM_EPS finchfsd -d /scr -v debug &
sleep 5 # wait for finchfsd to start

/tmp/finchfsd is the address file and generated on the compute node where finchfsd is started. FINCHFS client library connect to finchfsd by the address file.

Use FINCHFS client library

FINCHFS client library can be used by pkg-config.

$ export PKG_CONFIG_PATH=$PKG_CONFIG_PATH:/path/to/finchfs/lib/pkgconfig
$ pkg-config --cflags finchfs
-I/path/to/finchfs/include -I/path/to/ucx/include
$ pkg-config --libs finchfs
-L/path/to/finchfs/lib -L/path/to/ucx/lib -lfinchfs -lucp -luct -lucs -lucm

First, write application code hello.c.

#include <stdlib.h>
#include <fcntl.h>
#include <finchfs.h>

int
main(int argc, char **argv)
{
    if (finchfs_init(NULL)) {
        return (-1);
    }
    int fd;
    if ((fd = finchfs_create("/hello", 0, S_IRWXU)) < 0) {
        return (-1);
    }
    if (finchfs_close(fd)) {
        return (-1);
    }
    finchfs_term();
    return (0);
}

Second, compile the application code.

$ gcc `pkg-config --cflags finchfs` hello.c `pkg-config --libs-only-L finchfs | sed 's/-L/-Wl,-rpath,/g'` `pkg-config --libs finchfs`

Finally, run the application code.

$ ./a.out

We can set environment variables for FINCHFS client library.

• FINCHFS_LOG_LEVEL : specifies the log level (e.g. debug). Default is info.

• FINCHFS_CHUNK_SIZE : specifies the chunk size. Default is 64 KiB.