The swap is at low usage, and the OS sometime run out of memory and start scarifying processes
swapon -s
Filename Type Size Used Priority
/dev/vda1 partition 2047992 75030 1
Memory is around 97% used. any idea what is wrong ? I tried turning swap off/on, that did not help.v
Centos 6.5 / kernel 2.6.32
cat /proc/meminfo
MemTotal: 15000800 kB
MemFree: 300532 kB
Buffers: 11364 kB
Cached: 211224 kB
SwapCached: 0 kB
Active: 12613992 kB
Inactive: 1854012 kB
Active(anon): 12555272 kB
Inactive(anon): 1690320 kB
Active(file): 58720 kB
Inactive(file): 163692 kB
Unevictable: 0 kB
Mlocked: 0 kB
SwapTotal: 2047992 kB
SwapFree: 2047992 kB
Dirty: 68 kB
Writeback: 0 kB
AnonPages: 14245460 kB
Mapped: 19440 kB
Shmem: 176 kB
Slab: 76136 kB
SReclaimable: 48572 kB
SUnreclaim: 27564 kB
KernelStack: 2400 kB
PageTables: 35352 kB
NFS_Unstable: 0 kB
Bounce: 0 kB
WritebackTmp: 0 kB
CommitLimit: 9548392 kB
Committed_AS: 7996680 kB
VmallocTotal: 34359738367 kB
VmallocUsed: 40680 kB
VmallocChunk: 34359684884 kB
HardwareCorrupted: 0 kB
AnonHugePages: 9834496 kB
HugePages_Total: 0
HugePages_Free: 0
HugePages_Rsvd: 0
HugePages_Surp: 0
Hugepagesize: 2048 kB
DirectMap4k: 9204 kB
DirectMap2M: 15417344 kB
swappiness looks ok
cat /proc/sys/vm/swappiness
60
Best Answer
Very interesting you have almost 300 MB free and 200 cached probably your swappines it's not aggressive , I played many times in my past with this in order to have more performance with hosted VPS , so you have to change your vm.swappiness kernel parameters to set a fine threshold for you these links are good for you but take care test it before go in production.
https://askubuntu.com/questions/103915/how-do-i-configure-swappiness https://en.wikipedia.org/wiki/Swappiness
I hope it helps!