[CentOS] Re: Re: Not seeing all memory in CentOS 5.1 x86_64

Ruslan Sivak russ at vshift.com
Wed Jun 11 17:37:16 UTC 2008

henry ritzlmayr wrote:
> Am Mittwoch, den 11.06.2008, 10:06 -0700 schrieb MHR:
>> On Wed, Jun 11, 2008 at 8:36 AM, Ruslan Sivak <russ at vshift.com> wrote:
>>> I guess it has something to do with the ballooning driver for Dom0.  It
>>> looks like I just tried to allocation too much memory to DomU and the box
>>> went down hard.  I think there's a setting in xen to the min amount of
>>> memory to go down to, but I'm not sure why Dom0 is using 600mb of RAM.  Is
>>> there a mini installation of CentOS that I can do that would use less RAM?
>>>  I've already unchecked all the boxes when installing CentOS. I would like
>>> Dom0 to be as small as possible, both due to RAM usage and from a security
>>> perspective.
>> I've not familiarized myself with xen yet, but have you considered
>> VMware Server?  I haven't had any serious problems with it, and none
>> at all since v1.0.5 came out (1.0.6 is the current one).  Works
>> nicely, stays within its memory allocation, and top et al work as
>> you'd expect them to.
>> HTH
>> mhr
> I evaluated VMware Server myself (v1.0.3) and at that time, Disk I/O was
> pretty bad within a virtual machine. The only solution I found was XEN
> with paravirtualization. Has there been any progress on that with later
> releases?  
> For example: 
> dd if=/dev/md5 of=/dev/null bs=1M count=1000 on bare metal gave 272 MB/s
> same within VMware gave only 47,9 MB/s
> I know that dd is not a benchmark - but for measuring sequential reads
> within a system its fair enough for me.
> Henry

This was another reason that I went with Xen, although my testing method 
at the time was flawed.  I've been using hdtune to measure windows 
performance, but it was giving me 70mb/s across the board.  I'm using 
IOmeter now and I will try to reinstall VMWare to see what the 
performance difference is.


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