zfs memory calculation
807557Jun 9 2010 — edited Jun 17 2010Hi All,
We are using zfs in our servers, as all known that zfs having the property of memory caching, while searching through internet i found the arc_summary.pl script to see the memory usages. The output shows as below,
System Memory:
Physical RAM: 16375 MB
Free Memory : 668 MB
LotsFree: 250 MB
ZFS Tunables (/etc/system):
ARC Size:
Current Size: 4615 MB (arcsize)
Target Size (Adaptive): 10514 MB (c)
Min Size (Hard Limit): 1918 MB (zfs_arc_min)
Max Size (Hard Limit): 15351 MB (zfs_arc_max)
ARC Size Breakdown:
Most Recently Used Cache Size: 100% 10514 MB (p)
Most Frequently Used Cache Size: 0% 0 MB (c-p)
ARC Efficency:
Cache Access Total: 1991616
Cache Hit Ratio: 88% 1763516 [Defined State for buffer]
Cache Miss Ratio: 11% 228100 [Undefined State for Buffer]
REAL Hit Ratio: 87% 1736361 [MRU/MFU Hits Only]
Understand the Physical Ram and free memory (same as top or vmstat output) , beyond this how to find out the actual free memory (by subtracting or adding the cache or free memory .....)