Take a look at this link.
Here your system has a free RAM , approximately
3GB. But the system is still using swap space.
- The system can do a swap in/out from the swap space as and when required.
- But if there are many swap in/out operations i.e many disk operations, eventually this will effect the performance of applications. With aggressive swapping the effect on your database could be that the Query takes longer to fetch the results.There could be an overall impact on the system performance.
- Just to get a fair bit of idea of how your system is functioning, run the
sar -B command and observe the column
Calculated as pgsteal / pgscan, this is a metric of the efficiency of page reclaim. If it is near 100% then almost every page coming off the tail of the inactive list is being reaped. If it gets too low (e.g. less than 30%) then the virtual memory is having some difficulty. This field is displayed as zero if no pages have been scanned during the interval of time.
The sample output of
sar -B 1:
05:12:13 PM pgpgin/s pgpgout/s fault/s majflt/s pgfree/s pgscank/s pgscand/s pgsteal/s %vmeff
05:12:14 PM 0.00 294.95 33.33 0.00 313.13 0.00 0.00 0.00 0.00
05:12:15 PM 8.00 377.00 35.00 0.00 433.00 0.00 0.00 0.00 0.00
Checkout this link for the procedure to add swap space.