Re: [Xen-users] Memory problems persist... Cannot allocate memory

[Jean-Paul Pozzi <jpp@xxxxxxxxxxxxxxxxxx>]

----- Mail Original -----
De: "James Pifer" <jep@xxxxxxxxxxxxxxxx>
Ã: xen-users@xxxxxxxxxxxxxxxxxxx
EnvoyÃ: Dimanche 24 Janvier 2010 15:47:58
Objet: Re: [Xen-users] Memory problems persist... Cannot allocate memory


> > 
> 
> Hello,
> 
> I see that your Dom0 has 33543988k #32GB, is it all the memory in the
> server?
> If so it is possible that after some "ballooning" and memory allocation
> the memory is too unorganized that the allocator can't find suitable
> chunks of memory. I had had that problem after a system upgrade where
> the "menu.lst" (or grub.fcg) was recreated without the tuning
> parameters.
> I think that 32GB is fa too much for the Dom0, usually Dom0 is limited
> to a value between 1024M and 3072M with the dom0_mem=xxxx in the
> grub.cfg, the memory of Dom0 is mainly used for buffer cache on behalf
> of the Domus. 
> It is also often useful to use the parameter "dom0_min_mem=xxx" in the
> xend.config file. In my systems I use the same value eg : 
> (dom0-min-mem 2048)  
> (enable-dom0-ballooning no)   
> in xend-config.sxo
> and
>  multiboot       /xen-3.4.gz /xen-3.4.gz noreboot dom0_mem=2048M 
> in grub.cfg.
> I have had problems with "ballonning yes" if domUs are stopped and
> started many times without a server reboot (memory fargmentation ?).
> 
> Regards
> 
> JP Pozzi


No, dom0 has 4gb (was lower but was trying 4gb to see if it helped)
dom0_min_mem is set to 512M
Ballooning is disabled. 

>From menu.lst:
###Don't change this comment - YaST2 identifier: Original name: xen###
title Xen -- SUSE Linux Enterprise Server 11 - 2.6.27.19-5
    root (hd0,1)
    kernel /boot/xen.gz  dom0_mem=4096M 
    module /boot/vmlinuz-2.6.27.19-5-xen 
root=/dev/disk/by-id/scsi-200d0b29d2d004400-part2 
resume=/dev/disk/by-id/scsi-200d0b29d2d004400-part1 splash=silent showopts 
vga=0x317
    module /boot/initrd-2.6.27.19-5-xen

See xen-config.sxp below. 

Thanks,
James

Hello,

If you set "dom0_mem=4096M" try to set "dom0_min_mem=4096" in xend-config.sxp
You said that the system ran a long time before showing "can't allocate memory"
it could be a problem with memory fragmentation or a memory leak.
I saw something about that setting a long time ago, but I always use it.

Regards

JP Pozzi



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