Thanks for the info, that's a great help.

BTW,

1. when i change "mem=128M" to "mem=64M", seems it didn't help, still uses the same amount of /dev/shm.
    why ?

2. Where did you learn the /dev/shm info for uml ? 

Have a nice day !

> Date: Sun, 11 Dec 2011 03:20:44 -0600
> Subject: Re: [uml-user] The max instance of uml is limited by memory and disk size ?
> From: clownix@clownix.net
> To: ningji@hotmail.com
> CC: user-mode-linux-user@lists.sourceforge.net
>
>
> Hello,
> For UML machines, you have to look carefully at the /dev/shm value with
> df, if the used up /dev/shm gets too high, new UML cannot be launched.
>
> To look at the value you have:
> df -h /dev/shm/
>
> To change it to 2 giga:
> mount -t tmpfs shmfs -o size=2g /dev/shm
>
> Look again:
> df -h /dev/shm/
>
>
>
>
>
> >
> > Hi all,
> > when i run 60 umls in the same host with "mem=128M""free -m" says almost
> > no free memory left.
> > if i run more, all umls got killed.
> > Now if i run uml with "mem=64M", was trying to run 100 umls, but still got
> > terminated.Why ?
> > (our goal is to run 200 umls in each host, 4GB memory each host.)(Also
> > disk size is big enough, each rootfs is 0.1 G, 100 of umls is 10G)
> > Thanks !
> >
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