Virtual Storage on System i5

I have been looking into the possibilities available to users of the new Virtual Storage options for the System i5. Virtual Tape was recently announced in Version 5 Release 4 but Virtual Optical has been available since V5R1. I never really looked at the options until I was reviewing one of my old products CDG/400. This product allowed you to create CD’s which were recognized in the System i5 Drive allowing you to do such things as restore licensed programs etc. I used this technology to create my Licensed Program Product Installation CD’s for all the products I produced. But a problem I discovered was having to save to tape just what you needed on the CD, then copy the data from the Tape drive to an IFS image before cutting it to a CD on a PC! this took a long time, the small programs that I produced took approxitmately 1 hour to create everytime I made a change no matter how small. So as you guessed I gave up and used an alternative solution which was to create IFS based Save Files and use those for distribution of the products. It was easy to FTP the objects around and do the copy from the IFS into a save file (CPYFRMSTMF).

But I was thinking OK so now IBM has Virtual Tape would that speed up the process because I could read the file as if it was a tape file and it would be a lot quicker. Unfortunately I had a number of problems, mainly because I wrote the code a long time ago and it wasn’t too well commented so it failed to run with little or no output showing why! I then thought OK lets look at how the Virtual Optical works! I was surprised to see just how easy it was to set up and run! thats not to say I didnt have a few challenges, but I did get it up and running after reading a few more pages of the manuals! (Yes typical male I dont need manuals)

I set up my nightly saves to run to the Virtual Optical and left it to run! Next morning I came in to find the object sitting exactly where it should be on the IFS. Being a HA specialist I knew that I had to get the data off the i5 for security and to free up some of the DASD, it is a full save of my user libs and obviously important that I can recover if the system looses a disk or something.

I could FTP the object to the PC I had sitting around with a reasonable amount of DASD (1TB) and I was happy that should I need to recover I would just have to restore either from the DASD (FTP back to the i5) or cut a CD from the iso image.

I was having a few problems cutting the image so I started to test out the save while I was watching it, I found that I could do the full nights save in less than 4 minutes! My normal save would run for 40 minutes minimum or a couple of hours if I did a TAPE Clear *YES. This was a big incentive for me to push to the next stage which was to automate the whole process.

I read few articles about how to automatically FTP from the i5 to another FTP server. After a lot of fiddling I managed to get the FTP process to work and set up my night save programs to automatically send the images to a remote FTP server (just happens to be a Linux box now). All ran well for a few weeks until I found a problem with the Virtual Optical process, if you fill a volume the OS will send an OPT149F to the QSYSOPR message queue asking for you to attach a new one! This was not what I wanted as I dont have a monitor on the queue and didnt want to add an auto response entry for the message because I may need to hold the process at other times.

The solution I created was quite simple, I just created a couple of volumes before the save started. This will continue to run until I get to the stage where I need to attach another one… However I have found alternatives which I will discuss in another Blog about the STRWCH commands and API’s available in V5R4. The beauty of the solution is that I dont have to worry about the tape being cleared, I can issue the command on the Virtual object and its done in seconds! Plus when I FTP to the store I overwrite the existing object (by default and design, I dont want to have lots of previous copies available). So I now have a save process which runs every night and takes approximately 6 minutes to complete including the FTP to the store (its over a 10mb ethernet connection) and I have a level of recoverability I didnt have before! Plus I am just using up some DASD which cost me less than $600 for a TB, i5 DASD is not cheap!

A couple of things I need to resolve before I move forward will be the ability to log all data as it is stored on the images, allow automatic retrieval from the remote source over FTP (NearLine storage)and have the images mapped to a directory structure which would allow me a more flexible save process and eventually better save strategy.

My intention is to fully document the process I followed plus the code I used. This will come later, at the moment I am still having fun writing this blog! Plus I have a lot more I would like to share such as the STRWCH commands and API’s…

If you want to see the code before I get the white papers done let me know, I may publish here (with appropriate changes)


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