Severe instabilities and system lockups

[Adam Vande More]

On Thu, Mar 11, 2010 at 5:05 PM, David Jackson <djackson452 at gmail.com>wrote:

> David Jackson wrote:
>
>> I am still having severe problems with severe system instabilities with
>> FreeBSD and have had these problrms in 7.1 and 8.0. The system randomly
>> locks up, it appears applications lock up when they access the USb disk.
>> Also, when accessing the USB disk, the entire system lockup often for
>> minutes. Performance with accessing USB disks is horrendous,. it took 7
>> hours to copy a directory that was 200 MB. Any program that accesses the USB
>> disk tend to freeze for minutes, and often the entire system becomes
>> unresponsive for minutes. Overall FreeBSD here is characterized by severe
>> instabilities, ive had better performance from Windows 98 systems. The fact
>> that the entire system freezes up, this should not happen, a well designed
>> system will not lock up the entire OS when accessing disk.
>>
>> Are there any diagnostic tools uch as getting a log of tranmissions on USB
>> and probe it, ,or finmd out what code it is lockilng up on ?Has anyone else
>> seen these problems with USB disks?
>>
> Thank you for the reply to my concerns. I have been reading through them
> carefully.
>
> I seem to have also discovered that the lockup problems are not entirely
> due to USB issues. Many of them were being caused by an apparent problem
> with the swap system. I have two swaps, a file backed swap and a partition
> swap on the same disk. Apparently when having two swaps on the disk there
> are severe performance problems. FreeBSD needs to fix whatever is causing
> this thrashing problem. So far the lockups have seem to become much less
> severe since i have disabled the file based swap file. I may disable the
> partition swap but i do not know if it is possible to have the system boot
> with a file based swap only. Perhaps i can disable the partition swap after
> it boots.
>
> I am trying to copy a directory on the USB drive however and it does seem
> to be rather slow still. It started at 5:45 and is still going. I will see
> how long it takes.
>
>
> Again thanks for the help with these issues


It's unclear how this system is being used, but if swap is being frequently
accessed that's a problem your usage, not freebsd in particular.  If your
swap is being accessed frequently in any OS you should expect a serious
performance hit.  If that is the case you should investigate reducing memory
usage/adding more in.

-- 
Adam Vande More