Hi,
I am trying to understand in details what is the ratio between metadata and
data in ARC and L2ARC for my system.
Looking at 'kstat -n arcstats', I see:
ARC Current Size: 19217 MB (size=19,644,754,928)
ARC Metadata Size: 112MB (hdr_size=117,896,760)
I am trying to understand what l2_hdr_size means? Is this the metadata stored
in ARC used to reference L2ARC content? or is it metadata stored in L2ARC? If
the former, where the size of the metadata located in ARC to reference L2ARC
content?
In general, I am trying to decide if my L2ARC should only store metadata or
metadata+data. My workload is very random and *I think* does not benefit from
caching.
Here is the full output:
kstat -n arcstats
module: zfs instance: 0
name: arcstats class: misc
c 19644817124
c_max 24686542848
c_min 3085817856
crtime 139.366765387
data_size 18459594240
deleted 111310878
demand_data_hits 56990788
demand_data_misses 631678
demand_metadata_hits 391511844
demand_metadata_misses 23702633
evict_skip 8773774
hash_chain_max 16
hash_chains 362312
hash_collisions 142969185
hash_elements 1257608
hash_elements_max 1368567
hdr_size 117896760
hits 505821153
l2_abort_lowmem 165
l2_cksum_bad 0
l2_evict_lock_retry 2219
l2_evict_reading 0
l2_feeds 1407223
l2_free_on_write 5785987
l2_hdr_size 116243656
l2_hits 16984766
l2_io_error 0
l2_misses 8707048
l2_read_bytes 93748148736
l2_rw_clash 972
l2_size 63115001856
l2_write_bytes 5882913534976
l2_writes_done 958486
l2_writes_error 0
l2_writes_hdr_miss 3397
l2_writes_sent 958486
memory_throttle_count 108
mfu_ghost_hits 15023125
mfu_hits 422352855
misses 25693849
mru_ghost_hits 2680252
mru_hits 29672107
mutex_miss 525565
other_size 961128416
p 18417019126
prefetch_data_hits 925997
prefetch_data_misses 440681
prefetch_metadata_hits 56392524
prefetch_metadata_misses 918857
recycle_miss 27494219
size 19644754928
snaptime 843583.792905623
--
This message posted from opensolaris.org
