HP-UX

Hi All,

Here is output of swapinfo -t from a server which has been giving

TNS-00519: Operating system resource quota exceeded
HPUX Error: 12: Not enough space

The server has been stable for 7 days now since some more swap space was added.

2 questions

1. Will the above error occur again when the total use hits 100% currently at 95%

2. Why does the memory only state 4.7GB where the server has 6GB of physical memory.

Thanks for any info

Mat

Code:

$ swapinfo -t
             Kb      Kb      Kb   PCT  START/      Kb
TYPE      AVAIL    USED    FREE  USED   LIMIT RESERVE  PRI  NAME
dev     2146304  469820 1676484   22%       0       -    1  /dev/vg00/lvol2
dev     1687552       0 1687552    0%       0       -    2  /dev/vg00/lvswap1
dev     1687552       0 1687552    0%       0       -    2  /dev/vg00/lvswap2
reserve       - 4836664 -4836664
memory  4786844 4463044  323800   93%
total   10308252 9769528  538724   95%       -       0    -

.

Are you saying that this box is at 95% after adding swap?

1. You cannot use more than 100% of your virtual memory. If you try, some horrible error will occur. At the time this swapinfo was performed, the box was nearly out of virtual memory. Maybe that 1/2 GB left is enough, but if not, the box will be unable to create new processes.

2. Originally Unix required swap area for any virtual object. So you first 6 GB of swap would simply enable the use of your 6GB of physical memory. Any swap after that gives you additional space over the 6GB. Under this scheme, you could in theory swap everything out. You have the kernel parameter swapmem turned on (which is wise). So the kernel pretends that you have an extra swap area which is sized at 4.7 GB. This means that you no longer have enough real swap to completely empty memory. The kernel computes the size of this imaginary swap area as a fixed percentage of the physical memory size.

This box fully consumed physical memory some time ago. This does not affect stability but it can affect performance. To see how bad that is, you want to watch this box's scan rate. (sr in the vmstat display).

Thanks very much for the info.

Cheers

Mat