[oi-dev] Plans to lower minimum memory requirements?

[Julian Wiesener]

Hi Olga,

On 03/17/11 08:51 PM, ольга крыжановская wrote:
> btrfs claims to use less memory than zfs but is still a COW design and
> openSUSE with btrfs runs smoothly in a vmware box with 384MB assigned.
> How is this possible?

actually the ZFS, the Datacache, COW and the even more important (for
small memory sizes) Metadatacache is not the biggest Problem here. The
kernel it self without ZFS Caches consumes much more Memory than a
typical Linux kernel, we would need to check if and where we can reduce
the size (more at Illumos scope).


(oi_148 i86pc)# echo '::memstat' | mdb -k
Page Summary                Pages                MB  %Tot
------------     ----------------  ----------------  ----
Kernel                     120290               469   23%
Anon                       166739               651   32%
Exec and libs                6381                24    1%
Page cache                  26215               102    5%
Free (cachelist)            66591               260   13%
Free (freelist)            133495               521   26%

Total                      519711              2030
Physical                   519710              2030

(oi_148 i86pc)# echo '::arc' | mdb -k
...
p                         =        60 MB
c                         =        64 MB
c_min                     =        64 MB
c_max                     =       481 MB
size                      =        99 MB
hdr_size                  =   1969824
data_size                 =  64107520
other_size                =  38426984
...
arc_meta_used             =        99 MB
arc_meta_limit            =       120 MB
arc_meta_max              =       107 MB





> Is there any thing else we can do to optimize Openindiana?

Yes, the main problem is actually not ZFS or the kernel, what it really
makes OI unusable to systems with smaller memory-size than 2GB is the
fact. that IPS (pkg commands, as well as beadm) are consuming much
memrory during upgrade/install. If you really want to make OI less
memory consuming, IPS is the point to start.
IPS is currently still developed open, people at oracle are working on
reducing the memory footprint and we have currently no plans or need to
fork IPS, so if you want to help in this area, i guess the best would it
be to join the upstream project.

Personally i really would apprechiate an effort (i really hated it to
buy an additional 1GB DIMM for my laptop just to be able to update) to
reduce the memory footprint of OI.
However, OI is actually not designed to be a small-hardware-desktop
system. There are many operation systems (even a few osol based) which
fits better into that scope and we currently have more urgends issues.
We are aiming on moving to illumos and create a base for a stable server
distribution and we'll have a lot to do to archive this first priority goal.


Regards,
Julian