MSS Intro | Multiple MSSes | /public Data | Wrapper Scripts | Tips and Traps

MSS Wrapper Scripts

Why Not NFS?

Unfortunately, we've had a very spotty record of success in accessing the new MSSes using NFS here at the Laboratory. Different types of problems have been encountered, particularly with Sun machines, which cause things from useless error messages to system hangs. And when the system that hangs is your division server, repeated reboots is not that way to engender good will for the new MSSes or your system administrators.

Because of this, NFS access has been disabled to the new MSSes.

In order to work around these problems in a manner that tries to preserve much of the convenience of using NFS, wrapper scripts around rsh/ssh have been written.

The Wrapper Scripts

These wrapper scripts are provided:

  • mssLs  --  list files on the new MSSes
  • mssGet  --  retrieve files from the new MSSes in a more efficient manner
  • mssPut  --  copy files to the new MSSes
  • mssChmod  --  change the permissions of files on the new MSSes
  • mssMkdir  --  make directories on the new MSSes
  • mssRmdir  --  delete directories from the new MSSes
  • mssRm  --  delete files/directories from the new MSSes

General Caveats

In general, these things need to be kept in mind about the wrapper scripts:
  • all MSSes may be transparently referenced as '/mss'
  • each of these scripts are wrapped around rsh/ssh (or rcp/scp). Thus:
    • the command-line arguments are limited to what rsh/ssh/rcp/scp support
    • file globbing (wildcard) characters are supported but must be quoted/escaped to protect them from the shell
    • users must have accounts set up for them on the new MSS host
  • no remote current working directory mechanism is supported
  • the wrapping requires as much as several dozen characters of its own, which limits command line lengths. There is no trapping of command-line length violations

mssGet is Special

mssGet is more than just a wrapper script around rcp/scp. It runs a special utility on the new MSS host that more efficiently orders tape accesses. In fact, using mssGet (when specifying multiple files to retrieve) is the fastest retrieval method available.