How to copy files as fast as possible?

Question

I am running my shell script on machineA which copies the files from machineB and machineC to machineA.

If the file is not there in machineB, then it should be there in machineC for sure. So I will try to copy from machineB first, if it is not there in machineB then I will go to machineC to copy the same files.

In machineB and machineC there will be a folder like this YYYYMMDD inside this folder -

/data/pe_t1_snapshot

So whatever date is the latest date in this format YYYYMMDD inside the above folder - I will pick that folder as the full path from where I need to start copying the files -

so suppose if this is the latest date folder 20140317 inside /data/pe_t1_snapshot then this will be the full path for me -

/data/pe_t1_snapshot/20140317

from where I need to start copying the files in machineB and machineC. I need to copy around 400 files in machineA from machineB and machineC and each file size is 1.5 GB.

Currently I have my below shell script which works fine as I am using scp but somehow it takes ~2 hours to copy the 400 files in machineA which is too long for me I guess. :(

Below is my shell script -

#!/bin/bash

readonly PRIMARY=/export/home/david/dist/primary
readonly SECONDARY=/export/home/david/dist/secondary
readonly FILERS_LOCATION=(machineB machineC)
readonly MEMORY_MAPPED_LOCATION=/data/pe_t1_snapshot
PRIMARY_PARTITION=(0 3 5 7 9) # this will have more file numbers around 200
SECONDARY_PARTITION=(1 2 4 6 8) # this will have more file numbers around 200

dir1=$(ssh -o "StrictHostKeyChecking no" david@${FILERS_LOCATION[0]} ls -dt1 "$MEMORY_MAPPED_LOCATION"/[0-9][0-9][0-9][0-9][0-9][0-9][0-9][0-9] | head -n1)
dir2=$(ssh -o "StrictHostKeyChecking no" david@${FILERS_LOCATION[1]} ls -dt1 "$MEMORY_MAPPED_LOCATION"/[0-9][0-9][0-9][0-9][0-9][0-9][0-9][0-9] | head -n1)

echo $dir1
echo $dir2

if [ "$dir1" = "$dir2" ]
then
    # delete all the files first
    find "$PRIMARY" -mindepth 1 -delete
    for el in "${PRIMARY_PARTITION[@]}"
    do
        scp -o ControlMaster=auto -o 'ControlPath=~/.ssh/control-%r@%h:%p' -o ControlPersist=900 david@${FILERS_LOCATION[0]}:$dir1/t1_weekly_1680_"$el"_200003_5.data $PRIMARY/. || scp -o ControlMaster=auto -o 'ControlPath=~/.ssh/control-%r@%h:%p' -o ControlPersist=900 david@${FILERS_LOCATION[1]}:$dir2/t1_weekly_1680_"$el"_200003_5.data $PRIMARY/.
    done

    # delete all the files first
    find "$SECONDARY" -mindepth 1 -delete
    for sl in "${SECONDARY_PARTITION[@]}"
    do
        scp -o ControlMaster=auto -o 'ControlPath=~/.ssh/control-%r@%h:%p' -o ControlPersist=900 david@${FILERS_LOCATION[0]}:$dir1/t1_weekly_1680_"$sl"_200003_5.data $SECONDARY/. || scp -o ControlMaster=auto -o 'ControlPath=~/.ssh/control-%r@%h:%p' -o ControlPersist=900 david@${FILERS_LOCATION[1]}:$dir2/t1_weekly_1680_"$sl"_200003_5.data $SECONDARY/.
    done
fi

I am copying PRIMARY_PARTITION files in PRIMARY folder and SECONDARY_PARTITION files in SECONDARY folder in machineA.

Is there any way to move the files faster in machineA. Can I copy 10 files at a time or 5 files at a time in parallel to speed up this process or any other approach?

NOTE: machineA is running on SSD

UPDATE:-

Parallel Shell Script which I tried, top portion of shell script is same as shown above.

if [ "$dir1" = "$dir2" ] && [ "$length1" -gt 0 ] && [ "$length2" -gt 0 ]
then
    find "$PRIMARY" -mindepth 1 -delete
    for el in "${PRIMARY_PARTITION[@]}"
    do
        (scp -o ControlMaster=auto -o 'ControlPath=~/.ssh/control-%r@%h:%p' -o ControlPersist=900 david@${FILERS_LOCATION[0]}:$dir1/t1_weekly_1680_"$el"_200003_5.data $PRIMARY/. || scp -o ControlMaster=auto -o 'ControlPath=~/.ssh/control-%r@%h:%p' -o ControlPersist=900 david@${FILERS_LOCATION[1]}:$dir2/t1_weekly_1680_"$el"_200003_5.data $PRIMARY/.) &
          WAITPID="$WAITPID $!"        
    done

    find "$SECONDARY" -mindepth 1 -delete
    for sl in "${SECONDARY_PARTITION[@]}"
    do
        (scp -o ControlMaster=auto -o 'ControlPath=~/.ssh/control-%r@%h:%p' -o ControlPersist=900 david@${FILERS_LOCATION[0]}:$dir1/t1_weekly_1680_"$sl"_200003_5.data $SECONDARY/. || scp -o ControlMaster=auto -o 'ControlPath=~/.ssh/control-%r@%h:%p' -o ControlPersist=900 david@${FILERS_LOCATION[1]}:$dir2/t1_weekly_1680_"$sl"_200003_5.data $SECONDARY/.) &
          WAITPID="$WAITPID $!"        
    done
     wait $WAITPID
     echo "All files done copying."
fi

Errors I got with parallel shell script-

channel 24: open failed: administratively prohibited: open failed
channel 25: open failed: administratively prohibited: open failed
channel 26: open failed: administratively prohibited: open failed
channel 28: open failed: administratively prohibited: open failed
channel 30: open failed: administratively prohibited: open failed
mux_client_request_session: session request failed: Session open refused by peer
mux_client_request_session: session request failed: Session open refused by peer
mux_client_request_session: session request failed: Session open refused by peer
mux_client_request_session: session request failed: Session open refused by peer
mux_client_request_session: session request failed: Session open refused by peer
channel 32: open failed: administratively prohibited: open failed
channel 36: open failed: administratively prohibited: open failed
channel 37: open failed: administratively prohibited: open failed
channel 38: open failed: administratively prohibited: open failed
channel 40: open failed: administratively prohibited: open failed
channel 46: open failed: administratively prohibited: open failed
channel 47: open failed: administratively prohibited: open failed
channel 49: open failed: administratively prohibited: open failed
channel 52: open failed: administratively prohibited: open failed
channel 54: open failed: administratively prohibited: open failed
channel 55: open failed: administratively prohibited: open failed
channel 56: open failed: administratively prohibited: open failed
channel 57: open failed: administratively prohibited: open failed
channel 59: open failed: administratively prohibited: open failed
mux_client_request_session: session request failed: Session open refused by peer
channel 61: open failed: administratively prohibited: open failed
mux_client_request_session: session request failed: Session open refused by peer
mux_client_request_session: session request failed: Session open refused by peer
mux_client_request_session: session request failed: Session open refused by peer
mux_client_request_session: session request failed: Session open refused by peer
mux_client_request_session: session request failed: Session open refused by peer
mux_client_request_session: session request failed: Session open refused by peer
mux_client_request_session: session request failed: Session open refused by peer
mux_client_request_session: session request failed: Session open refused by peer
mux_client_request_session: session request failed: Session open refused by peer
mux_client_request_session: session request failed: Session open refused by peer
mux_client_request_session: session request failed: Session open refused by peer
mux_client_request_session: session request failed: Session open refused by peer
mux_client_request_session: session request failed: Session open refused by peer
channel 64: open failed: administratively prohibited: open failed
mux_client_request_session: session request failed: Session open refused by peer
channel 68: open failed: administratively prohibited: open failed
channel 72: open failed: administratively prohibited: open failed
channel 74: open failed: administratively prohibited: open failed
channel 76: open failed: administratively prohibited: open failed
channel 78: open failed: administratively prohibited: open failed

Answer 1

you can try this command

rsync

from the

man rsync

you will see that: The rsync remote-update protocol allows rsync to transfer just the differences between two sets of files across the network connection, using an efficient checksum-search algorithm described in the technical report that accompanies this package.