Improve RMS and Disk Performance¶

1. Set RMS defaults for the account or process:

   $ SET RMS_DEFAULT/BLOCK=127/BUFF=255/NET=127/EXT=5000
   

   Throughput increases of 300% or more have been observed.

   Example:

   $ SCP 192.168.20.131:"test/linux.bck" []
   
   linux.bck               |   60MB | 1210.5 kB/s | TOC: 00:00:51 | 100%
   
   $ SET RMS/BLOCK=127/BUFF=255/NET=127/EXT=5000
   $ SCP 192.168.20.131:"test/linux.bck" []
   
   linux.bck               |   60MB | 3858.3 kB/s | TOC: 00:00:16 | 100%
   

   • If OpenVMS is the SCP/SFTP client, issue the RMS command before establishing the connection.
   • If OpenVMS is the SFTP server, place the command in the TCPIP$SSH account LOGIN.COM in the TCPIP$SSH_HOME directory.

2. Measure disk copy performance:

   Time a disk-to-disk copy of a large file (preferably 100 MB or larger).

   The TIME_COPY.COM procedure below is provided to assist when measuring the copy time.

   Disk fragmentation can significantly reduce performance. To minimize its impact:

   • Copy the file to a disk with little or no fragmentation (for example, a newly initialized disk).
   • Defragment the target disk by performing an image backup and restore or by using a utility such as Disk File Optimizer for OpenVMS (DFO).

   $! TIME_COPY.COM
   $ SET NOON
   $ SET PROC/PRIV=(ALL,NOBYPASS)
   $ CL == "TYPE/PAGE NL:"
   $ CL
   $ SAY == "WRITE SYS$OUTPUT"
   $
   $ T1 = F$TIME()
   $ SAY "STARTING TIME: ''T1'"
   $ SET PROC/UNIT=BYTES
   $ COPY/LOG 'P1' 'P2'
   $ T2 = F$TIME()
   $ H1 = F$EXTRACT(12,2,T1)*60*60
   $ M1 = F$EXTRACT(15,2,T1)*60
   $ S1 = F$EXTRACT(18,2,T1)
   $ SS1 = F$EXTRACT(21,2,T1)
   $ TS1 = H1+M1+S1
   $ H2 = F$EXTRACT(12,2,T2)*60*60
   $ M2 = F$EXTRACT(15,2,T2)*60
   $ S2 = F$EXTRACT(18,2,T2)
   $ SS2 = F$EXTRACT(21,2,T2)
   $ TS2 = H2+M2+S2
   $ TS3 = TS2-TS1
   $ SAY "ENDING TIME: ''T2'"
   $ SAY "TOTAL ELAPSED TIME:"
   $ SAY "''TS3' SECONDS."
   $ EXIT
   

   Example:

   $ @TIME_COPY.COM -
   _$ DISK10:[KITS.VMS.V84]TEST.FILE -
   _$ DKA0:[KITS]
   STARTING TIME: 13-DEC-2011 12:44:32.38
   %COPY-S-COPIED, DISK10:[KITS.VMS.V84]TEST.FILE;1
   copied to DKA0:[KITS]TEST.FILE;1
   (133.56MB)
   ENDING TIME: 13-DEC-2011 12:44:46.89
   TOTAL ELAPSED TIME:
   14 SECONDS.
   

   133.56 MB in 14 seconds equals approximately 9.54 MB/s (9540 KB/s).

   ---