VirtualBox uses nearly all memory (RAM + Swap)

[michael_sk]

I've installed VirtualBox-opensolaris-amd64-1.5.51-r28040-beta.gz on Solaris 10u4. I've installed Windows Vista (SP1) 32Bit as a VM (with 1 GB RAM assigned). When I start this VM, nearly all of my Host-Memory gets eaten up (3,8 of 4GB RAM + 1,8 of 2,0 GB Swap-Space).
When I close VirtualBox still 3,7 GB RAM is in use, but top or prstat shows no process with a huge size.

Has anyone else these problems or is this the normal behaviour?

[michael_sk]

I've found the explanation, I'm storing the Image-Files on a ZFS partition, so the kernel uses a lot of memory for caching... thats what I've just learned...

[Tomservo]

ZFS ARC shouldn't create so much memory pressure that it pushes anything else into the swapfile.

[huntp]

I seem to have a problem where VirtualBox is not releasing memory it's using ...

I have a single guest with 512MB RAM, and after a while it seems to consume all 2GB of my host (Ubuntu 7.10) memory.

If i stop my guest, the memory is eventually released (after approx 30secs). But, when it's running ... it consumes everything it can get!

See my output from "top":

top - 12:05:05 up 18:04, 3 users, load average: 1.06, 1.16, 0.82
Tasks: 59 total, 1 running, 58 sleeping, 0 stopped, 0 zombie
Cpu(s): 0.7%us, 49.5%sy, 0.0%ni, 47.2%id, 2.7%wa, 0.0%hi, 0.0%si, 0.0%st
Mem: 2075908k total, 2022772k used, 53136k free, 5028k buffers
Swap: 1510068k total, 108k used, 1509960k free, 1355020k cached

PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND
5253 jcomer 25 0 631m 596m 3340 S 100 29.4 35:47.73 VBoxVRDP
1 root 15 0 2952 1852 532 S 0 0.1 0:01.34 init
2 root 11 -5 0 0 0 S 0 0.0 0:00.00 kthreadd
3 root RT -5 0 0 0 S 0 0.0 0:00.00 migration/0
4 root 34 19 0 0 0 S 0 0.0 0:00.09 ksoftirqd/0
5 root RT -5 0 0 0 S 0 0.0 0:00.00 watchdog/0
6 root RT -5 0 0 0 S 0 0.0 0:00.00 migration/1
7 root 34 19 0 0 0 S 0 0.0 0:00.01 ksoftirqd/1
8 root RT -5 0 0 0 S 0 0.0 0:00.00 watchdog/1
9 root 10 -5 0 0 0 S 0 0.0 0:00.00 events/0
10 root 10 -5 0 0 0 S 0 0.0 0:00.00 events/1
11 root 20 -5 0 0 0 S 0 0.0 0:00.02 khelper
31 root 10 -5 0 0 0 S 0 0.0 0:00.00 kblockd/0
32 root 10 -5 0 0 0 S 0 0.0 0:00.00 kblockd/1
33 root 12 -5 0 0 0 S 0 0.0 0:00.00 kacpid

[jlliagre]

I have a single guest with 512MB RAM, and after a while it seems to consume all 2GB of my host (Ubuntu 7.10) memory.

This forum if for OpenSolaris hosts, not Linux.
In any case, unused RAM is wasted RAM.

[michael_sk]

ZFS ARC shouldn't create so much memory pressure that it pushes anything else into the swapfile.

... that's what I've heard too, but prstat and top showed nearly all memory (incl. swap) was used by the kernel. kmdb showed most of the memory was used by the zfs_arc.
Now I've set zfs:zfs_arc_max to 1GB and all looks better now and the system seems to work faster.