标签归档:vfs_cache_pressure

tune Linux physical memory

32G memory的Linux,跑一些application batch report,把archive redo log 搬到Tape上面,以及每天的Rman Full database backup,physical free memory只有35M

zzz ***Mon Dec 21 08:57:00 HKT 2009
MemTotal:     32889900 kB
MemFree:         35348 kB
Buffers:        109088 kB
Cached:       28892412 kB
SwapCached:       8592 kB
Active:        7049552 kB
Inactive:     24023160 kB
HighTotal:           0 kB
HighFree:            0 kB
LowTotal:     32889900 kB
LowFree:         35348 kB
SwapTotal:    16777208 kB
SwapFree:     16466904 kB
Dirty:            1628 kB
Writeback:           0 kB
Mapped:        6811368 kB
Slab:           839432 kB
CommitLimit:  33222156 kB
Committed_AS: 14507408 kB
PageTables:     801492 kB
VmallocTotal: 536870911 kB
VmallocUsed:    273416 kB
VmallocChunk: 536597367 kB
HugePages_Total:     0
HugePages_Free:      0
Hugepagesize:     2048 kB

通过调整vm参数来保证至少2G的physical free memory,避免负载上升时发生Swap导致CPU100%和node reboot

sysctl -w vm.min_free_kbytes=2097152
sysctl -w vm.vfs_cache_pressure=200

cd /proc/sys/vm
cat min_free_kbytes
cat vfs_cache_pressure

REF:http://www.oraclefans.cn/forum/showtopic.jsp?rootid=12006