arc_summary.pl (v0.3)Description: While ARC is an amazing achievement its memory consumption raises doubts and questions in many administrators and users who view memory as a precious commodity. The Kstat facility provides access to a variety of ARC counters, but interpretting these properly is complex and non-intuative in their raw form, without spending several hours in the arc.c code. The purpose of arc_summary.pl is to provide a historical analysis of the ZFS ARC, to answer such questions as:
arc_summary.pl is still under heavy development, take its results with a large grain of salt. (8/21/08) [code] |
|
S Y S T E M 1:
$ ./arc_summary.pl
System Memory:
Physical RAM: 32759 MB
Free Memory : 6734 MB
LotsFree: 511 MB
ZFS Tunables (/etc/system):
ARC Size:
Current Size: 39914 MB (arcsize)
Target Size (Adaptive): 31735 MB (c)
Min Size (Hard Limit): 3966 MB (zfs_arc_min)
Max Size (Hard Limit): 31735 MB (zfs_arc_max)
ARC Size Breakdown:
Most Recently Used Cache Size: 0% 0 MB (p)
Most Frequently Used Cache Size: 100% 31735 MB (c-p)
ARC Efficency:
Cache Access Total: 670097231886
Cache Hit Ratio: 98% 661915336214 [Defined State for buffer]
Cache Miss Ratio: 1% 8181895672 [Undefined State for Buffer]
REAL Hit Ratio: 93% 625641854637 [MRU/MFU Hits Only]
Data Demand Efficiency: 98%
Data Prefetch Efficiency: 99%
CACHE HITS BY CACHE LIST:
Anon: 4% 29431079074 [ New Customer, First Cache Hit ]
Most Recently Used: 0% 2122361572 (mru) [ Return Customer ]
Most Frequently Used: 94% 623519493065 (mfu) [ Frequent Customer ]
Most Recently Used Ghost: 0% 1773723345 (mru_ghost) [ Return Customer Evicted, Now Back ]
Most Frequently Used Ghost: 0% 5068679158 (mfu_ghost) [ Frequent Customer Evicted, Now Back ]
CACHE HITS BY DATA TYPE:
Demand Data: 73% 487401027055
Prefetch Data: 19% 126193017075
Demand Metadata: 2% 17287144100
Prefetch Metadata: 4% 31034147984
CACHE MISSES BY DATA TYPE:
Demand Data: 92% 7553812411
Prefetch Data: 0% 61829125
Demand Metadata: 2% 242779785
Prefetch Metadata: 3% 323474351
---------------------------------------------
S Y S T E M 2:
$ ./arc_summary.pl
System Memory:
Physical RAM: 16247 MB
Free Memory : 1064 MB
LotsFree: 253 MB
ZFS Tunables (/etc/system):
ARC Size:
Current Size: 5931 MB (arcsize)
Target Size (Adaptive): 5985 MB (c)
Min Size (Hard Limit): 507 MB (zfs_arc_min)
Max Size (Hard Limit): 15223 MB (zfs_arc_max)
ARC Size Breakdown:
Most Recently Used Cache Size: 73% 4405 MB (p)
Most Frequently Used Cache Size: 26% 1579 MB (c-p)
ARC Efficency:
Cache Access Total: 30934237785
Cache Hit Ratio: 99% 30933044424 [Defined State for buffer]
Cache Miss Ratio: 0% 1193361 [Undefined State for Buffer]
REAL Hit Ratio: 99% 30888972063 [MRU/MFU Hits Only]
Data Demand Efficiency: 99%
Data Prefetch Efficiency: 99%
CACHE HITS BY CACHE LIST:
Anon: 0% 43145095 [ New Customer, First Cache Hit ]
Most Recently Used: 0% 56656566 (mru) [ Return Customer ]
Most Frequently Used: 99% 30832315497 (mfu) [ Frequent Customer ]
Most Recently Used Ghost: 0% 280356 (mru_ghost) [ Return Customer Evicted, Now Back ]
Most Frequently Used Ghost: 0% 646910 (mfu_ghost) [ Frequent Customer Evicted, Now Back ]
CACHE HITS BY DATA TYPE:
Demand Data: 78% 24388331448
Prefetch Data: 19% 6013656064
Demand Metadata: 1% 472836583
Prefetch Metadata: 0% 58220329
CACHE MISSES BY DATA TYPE:
Demand Data: 21% 255389
Prefetch Data: 32% 385838
Demand Metadata: 31% 381534
Prefetch Metadata: 14% 170600
---------------------------------------------
|
