Speeding up SCP data transfers on the Sun SPARC T+ server line

I found the fowling Sun blog talking about SSH/SCP speed runing with the T1000/T2000 servers.

When using ssh or scp to transfer files to another server on the Niagara T1/2 boxes it will use only one virtual CPU which could be slow, as in the picture below

In contrast by using this script which also uses scp but copy’s in parllal the speed would increase drastically (depending on how many virtual CPU’s are used)

Note: that you might need to increase MaxStartups in server side sshd_config to 20 or higher. Alternatively, change conns=20 to conns=10 in pscp-test if you experience a problem, then restart sshd.

Before you use it, It is strongly suggest you to use this pscp test script that tests various download and upload transfers over localhost. You run it like this:

/tmp/pscp-test /var/tmp/user/pscp/ /tmp/pscp

The 1st parameter is a temporary directory with at least 0.5GB of free space, the 2nd argument is a full path to pscp script. You should see ALL TESTS PASSED as the last line of output and no obvious error output. If you don’t then do NOT use the pscp script and please report the problem to me.

Once all tests where successfully done, you could now run the pscp script like this

time /tmp/pscp -d -c 18 /var/tmp/user/sjsws-7_0-solaris-sparc.tar serverb:/tmp/

real    0m8.093s
user    1m11.351s
sys     0m17.169s

vs
time scp /var/tmp/user/sjsws-7_0-solaris-sparc.tar www18:/tmp/


real    0m38.269s
user    0m33.654s
sys     0m6.308s

pscp help
----
pscp - parallel data transfer based on SSH
Version 1.0
Usage: pscp user@host:file1 user@host:[dir | file2]
Options:
-b      block size in bytes (default: 65536)
-c      number of parallel connections (default: 6)
-d      debug mode
-h      this help
-q      quiet mode; print only errors
-s      SHA1 verification of the transfered file (use for debug only)
-t      test mode; no reads, no writes, transfer only

The scp copy will now run in parllal as seen in the image below.