Memory upgradation in ES40 Alpha server.

[Sk Noorul Hassan]

Whether the autogen is needed to run in order to let the Alpha VMS recognize the new higher memory capacity, after upgrading the memory from 1.5 GB to 2.5 GB or the new memory size as shown from >>> prompt will be recognised automatically by Alpha VMS after boot.

Please suggest

[Uwe Zessin · Accepted solution]

The system should recognize the additional memory automatically (it used to not do so, but those times are long gone). It is still a good idea to run AUTOGEN, because it will adapt a number of system parameters for the increased memory size.

[Kris Clippeleyr]

Hi,

In addition to what Uwe suggested (running AUTOGEN to adjust system parameters), it might also be a good idea to increase the size of the SYSDUMP.DMP file (or let AUTOGEN do it) and the pagefile(s).

Kris (aka Qkcl)

[comarow]

Alpha VMS will see the additional memory,
but it will not take full advantage of it.
(On a VAX you needed to either run autogen or set some sysgen parameters.)

That being said, you probably will want to resize your dump file, depending on the size and dump style.

Autogen will change some parameters to help take advantage of the additional memory, such as wsmax or perhaps your gblpages and modified page lists. After you've been up with your new system run autogen with feedback. Never let autogen reboot your system, check the results first and make sure they make sense.

I would be very carefull letting autogen resize page or swap files, and generally recommend people add a
pagefile=0
swapfile=0
to modparams.dat

With more memory, you probably will need less pagefile, but by default it will try and increase pagefile space. Instead it is better to monitor pagefile useage with
$show mem/file
and you want your pagefiles to be 50% free or at least have a couple of hundred thousand free blocks.

You can look in the file autogen feedback creates, agen$feedback.dat for peak page file useage and determine if you need additional page file space.


As a warning, autogen on old system disks will want to increase the size of pagefiles and attempts to create a new larger pagefile. However, due to fragmentation, it actually creates a smaller page file and you are really in trouble! Autogen really should only, (in my opinion) only be used to create initial pagefiles.

So, yes, run autogen with feedback, but please don't let it change the size of your pagefiles. You can read the report to see what it would have done.

Your dumpfile is another case. For example, if dumpstyle is 0, you won't be able to write a crash at all. Autogen does a good job of sizing dumpfiles.

Bob