With expanded storage VM provides a multi-level paging structure.  More
frequently used pages would typically live in expanded storage so that
they can be 'paged in' faster.  Less frequently used pages will migrate
to disk naturally.  There should be a fair amount of doc on the VM web
site that describes this in much more detail.

Allocating expanded storage to a Linux machine will 'dedicate' that
storage to the Linux guest, it can not be used by anyone else.  I would
think that your current swap concept is the most preferred.


On Thu, 2003-10-16 at 07:26, Daniel Jarboe wrote:
> With our RH guests we use a 64MB vdisk as our highest priority swap
> device, backed up by a 128MB swap minidisk "just in case".  The LPAR is
> currently configured without expanded storage, BUT this weekend we're
> bringing some in with an IPL.
>
> I presume SuSE SLES 8 includes the xpram driver?  I wonder if I should
> consider XSTOR for my "backup" swap volume rather than minidisk.  Since
> it's coming from XSTOR, does it need to be initialized like VDISK does,
> with something like the MKSWAP EXEC?
>
> Presumably if guests don't have XSTOR defined, z/VM will still use it
> for something.  The LPAR is being reconfigured with XSTOR based on
> various recommendations... at the expense of some real storage (no
> additional storage is being configured to the LPAR).  z/VM is supposed
> to be a better performer under this configuration?
>
> Thanks for any info,
> ~ Daniel
>
> > With the xpram driver Linux can use expanded storage as
> > another disk I/O
> > device, typically for paging or anything that requires very fast
> > access.  You might be better off removing it and using VDISK for a
> > paging device.
>
>
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