# OS freezes - possible high RAM utilization issue



## a_h (Jun 30, 2011)

Hi guys!

My system http://pastebin.com/DHjdgzwr keeps freezing after being up for several days. I have not been able to find any useful kernel dump info. While being up for several days system memory looks like this:


```
Mem: 616M Active, 609M Inact, 719M Wired, 3240K Cache, 622M Buf, 3991M Free
Swap: 4096M Total, 4096M Free
```

Before freezing, it looks:


```
Mem: 1249M Active, 3470M Inact, 912M Wired, 58M Cache, 622M Buf, 249M Free
Swap: 4096M Total, 4096M Free
```

I monitor the server with Zabbix. When free memory (in Zabbix) drops to 200~100Mb, nine times out of ten the server locks up.   

I went over http://bit.ly/lQBy5g
My server's 
	
	



```
vm.defer_swapspace_pageouts=0
```
 and I don't use swap.

Any suggestions for a newbie?


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## SirDice (Jun 30, 2011)

Check if the hardware itself is fault free. You won't be the first that has bad memory.


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## a_h (Jun 30, 2011)

FreeBSD along with a couple of Windows 2008 DCs, run as VMs on Citrix XenServer. Windows 2008 machines run like champs (which is unusual , FreeBSD does not


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## tingo (Jul 2, 2011)

Well, does XenServer have tools that allow you to look into the health of your VMs? VM logs, that sort of things?
(I only use VirtualBox, so I am not familiar with details of XenServer). 
One thing you can try to do, is to boot your FreeBSD machine verbose, and see if there are any suspicious messages in /var/log/messages before the server hangs.


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## tingo (Jul 3, 2011)

More hints:

One: is your virtual FreeBSD machine using SMP (i.e. more than one CPU?). If so, try to adjust it to only one CPU, and see if the freezes disappear.
Two: are the FreeBSD guest additions installed? If not, install them and see if it makes a difference.
Three: are you using ntpd(8)? If so, try disabling it, and see if that removes the freezes.


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## a_h (Jul 3, 2011)

Will try and let you know.


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