windows guests hangs; swapping very high..

[ssgam]

Hi All,

am not sure if this is observed before ...

1 have 3 windows guests configured (on opensolaris host).

the guests are all configured with 4GB of ram, 100GB of
disk space.

the host has 24GB of ram and more than 900GB disk
space available.

when i start the 3rd guest, the entire system hangs.

when i rebooted and tried again, i saw that at around
the time of hang, the system was swapping badly.

before starting any of the guests, the free memory and scan
rate is good ...

> kthr memory page disk faults cpu
> r b w swap free re mf pi po fr de sr s0 s1 s2 s3 in sy cs us sy id
> 0 0 0 21372616 13681668 1671 4162 0 0 0 0 4551 -0 113 38 40 2354 14825 5322 1 1 98
> 0 0 0 18491300 9283496 101 1824 0 0 0 0 0 0 32 0 0 1457 5595 1715 1 0 99
> 0 0 0 18458476 9247128 2 9 0 0 0 0 0 0 4 0 1 1697 3061 1367 0 0 100
> 0 0 0 18450164 9236956 153 1037 0 0 0 0 0 0 34 8 8 1592 3913 1631 1 0 99
> 0 0 0 18369408 9125988 116 1755 0 0 0 0 0 0 28 28 28 2220 43185 13909 2 1 98
> ...

after starting the 3rd guest, and around the time of the hang, the free memory
is low, and the scan rate is very high..

> kthr memory page disk faults cpu
> r b w swap free re mf pi po fr de sr s0 s1 s2 s3 in sy cs us sy id
> 2 0 204 11616420 96100 1888 2134 535 5159 10921 0 14551427 0 1877 59 51 135578 55885 90896 1 11 88
> 2 0 216 11616424 97024 1829 2011 380 5201 11240 260 14613978 0 1722 4 3 137547 58131 72618 1 11 89
> 2 0 218 11616420 97568 2024 2190 355 4530 10522 0 14714477 0 2019 34 31 141525 60265 130612 1 12 88
> 2 0 224 11616428 98448 1765 1947 428 3882 9511 0 12753507 0 1005 11 9 94912 40081 82944 0 9 91

how does VB allocates memory to guests ? i'd assume that it wouldn't lock down
memory ?

even if it does, i'll have enough swap as well:

> swapfile dev swaplo blocks free
> /dev/zvol/dsk/rpool/swap 182,1 8 25155576 25155576

i'm using virtual box v4.0.0.

Thanks for any suggestions,
sam

MOD Edit: Cross posting is not allowed. Other post deleted.

[tomwaters]

Try moving to the latest box, I found it more stable....or try 3.12, also more stable than 4.0.0

[ssgam]

Thanks Tom,

i'll give them a try..

am concerned if the problem is os related, due to zfs..

cheers,
sam

[ch.eick]

Hi,
I had the same problem too.
My college told me to limit the ARC cache of zfs, because zfs is grabbing all free memory for caching.
On my system there is an raid-z with 4x1T running and I only have 8Gb Ram. After limiting the ARC cache...

ARC Cache limiting
> /etc/system
– set zfs:zfs_arc_max=2147483648 (only an example! It depends on you zfs size and performance)
– Active after reboot

it is now running

[Ramshankar]

how does VB allocates memory to guests ? i'd assume that it wouldn't lock down
memory ?

It does. Once you've assigned memory to a VM you must assume it will be locked down and unavailable to the host for other purposes. With RamPreAlloc all of the assigned memory is allocated on VM power-up without it (which is the default) the allocation happens in a lazy fashion.