Increased Anaconda memory requirements?

John Reiser jreiser at bitwagon.com
Sat Feb 26 15:50:37 UTC 2011


>>> http://anonbadger.wordpress.com/2011/02/25/need-more-memory/

>>> Why does Anaconda need more memory?  Such changes really need to be
>>> coordinated and documented better.  We need changes in several
>>> documentation including installation guide and release notes not to
>>> mention changes in the default RAM allocation in virt-manager and so
>>> on.  Can someone in the Anaconda team provide the details please.

>> AFAIK it's more or less a bug.

> I assumed it was because the initrd is bigger, at least in the PXE 
> case:
> 
> https://bugzilla.redhat.com/show_bug.cgi?id=680542

Much of this is not a bug, it is intentional.  The F14 way of
    32MB  isolinux/initrd.img
   155MB  images/install.img
    32MB  images/pxeboot/initrd.img  [same as isolinux/initrd.img]
has become in F15
   141MB  isolinux/initrd.img
     0MB  images/install.img  [not present]
   141MB  images/pxeboot/initrd.img  [same as isolinux/initrd.img]
[The part that *may* be a space-on-the-platter bug is that the .iso
might not "de-dup" isolinux/initrd.img and images/pxeboot/initrd.img
by sharing the extents for those files, which have identical contents.]

Note that 141MB < (32MB + 155MB) so that the .iso and the total size
of data fetched for any install can be smaller.  However the main reason
for the change is for simplicity and correctness in anaconda itself.
Having a separate "stage2" meant significant complexity and many bugs.

In this message, Will Woods says that using xz compression instead of
gzip can reduce the size of initrd.img to about 90MB:
https://www.redhat.com/archives/anaconda-devel-list/2011-February/msg00107.html
So that will reduce the size of downloaded data, but the expanded initramfs
could be almost the same size, requiring more RAM in F15 than F14.

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