On 22/01/14 23:53, Daniel Jitnah wrote: > FWIW: > > Its actually because of memory over-committment using ballooning virtio > device.
Sorry, I should rephrase the above: Its because of memory over-commitment on the host. This is managed using ballooning virtio device in the guest VM. > In theory the VM should get back the missing memory when > needed, assuming its available elsewhere on the host!!! > Daniel. > > > > On 22/01/14 19:20, Craig Sanders wrote: >> On Wed, Jan 22, 2014 at 04:21:42PM +1100, Daniel Jitnah wrote: >>> I have tried that (free --si) , it reports 778 (or something like >>> that_. Btw its Debian 7. >>> >>> The value 761 also seems like a weird number? >>> >>> Has anyone had any issue with Debian reporting wrong memory? >> >> some vaguely relevant thoughts in no particular order: >> >> >> the kernel always uses some ram for itself, and any data in tmpfs >> filesystems will use ram too. >> >> 220MB or 240MB out of 1GB sounds like a lot, though....is the initrd >> still mounted? or maybe some ram is being reserved for a video card or >> other device (unlikely, most VMs only use around 10M or so for video >> emulation)? >> >> IMO, the most likely culprit is your VM hypervisor - kvm or xen? or >> maybe your kernel version - do you get different values for 'free' with >> different kernels? >> >> try grepping for "Memory" in /var/log/dmesg, e.g. on my 16GB system I >> get: >> >> # uname -a >> Linux ganesh 3.10-2-amd64 #1 SMP Debian 3.10.7-1 (2013-08-17) x86_64 >> GNU/Linux >> >> # grep Memory /var/log/dmesg >> [ 0.000000] Memory: 16346352k/17563648k available (3642k kernel code, >> 826012k absent, 391284k reserved, 3127k data, 920k init) >> >> # free -m >> total used free shared buffers cached >> Mem: 16047 15695 351 146 0 829 >> -/+ buffers/cache: 14866 1181 >> Swap: 8191 3681 4510 >> >> >> (note: "absent" memory is irrelevant and can be ignored, it just >> indicates gaps in the motherboard's memory map...it's not actually >> missing memory - for details, see >> http://serverfault.com/questions/220626/debian-squeeze-and-available-memory-1gb-absent >> ). >> >> some other words to grep for are (case-insensitive) "mem" and "ram". >> >> >> also, has the VM been allocated 1000M or 1024M? it's not that great a >> difference, but it all adds up. >> >> >> craig >> > _______________________________________________ > luv-main mailing list > [email protected] > http://lists.luv.asn.au/listinfo/luv-main > _______________________________________________ luv-main mailing list [email protected] http://lists.luv.asn.au/listinfo/luv-main
