Date: Fri, 2 Oct 2009 00:22:27 +0400 From: Alexander Shevchenko <pepelac@gmail.com> To: freebsd-fs@freebsd.org Subject: ARC & L2ARC efficiency Message-ID: <8c9ae7950910011322j1a6b66fcp73615cc17ae20328@mail.gmail.com>
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Good time of day! How could i check the efficiency of ARC? Are total reads from pool equal kstat.zfs.misc.arcstats.hits + kstat.zfs.misc.arcstats.misses, or this values are just reads from cache? By efficiency i mean reads_from_cache/(reads_from_cache+reads_from_drives) Are there any document where kstat values described? zpool status pool: data state: ONLINE scrub: none requested config: NAME STATE READ WRITE CKSUM data ONLINE 0 0 0 da2 ONLINE 0 0 0 da4 ONLINE 0 0 0 cache da3 ONLINE 0 0 0 #sysctl kstat kstat.zfs.misc.arcstats.hits: 282927703 kstat.zfs.misc.arcstats.misses: 66220328 kstat.zfs.misc.arcstats.demand_data_hits: 164374119 kstat.zfs.misc.arcstats.demand_data_misses: 6615511 kstat.zfs.misc.arcstats.demand_metadata_hits: 88715021 kstat.zfs.misc.arcstats.demand_metadata_misses: 4464890 kstat.zfs.misc.arcstats.prefetch_data_hits: 28851210 kstat.zfs.misc.arcstats.prefetch_data_misses: 55109950 kstat.zfs.misc.arcstats.prefetch_metadata_hits: 987353 kstat.zfs.misc.arcstats.prefetch_metadata_misses: 29977 kstat.zfs.misc.arcstats.mru_hits: 44560461 kstat.zfs.misc.arcstats.mru_ghost_hits: 1493532 kstat.zfs.misc.arcstats.mfu_hits: 211027800 kstat.zfs.misc.arcstats.mfu_ghost_hits: 16337660 kstat.zfs.misc.arcstats.deleted: 49112923 kstat.zfs.misc.arcstats.recycle_miss: 9574100 kstat.zfs.misc.arcstats.mutex_miss: 252423 kstat.zfs.misc.arcstats.evict_skip: 2269320648 kstat.zfs.misc.arcstats.hash_elements: 644877 kstat.zfs.misc.arcstats.hash_elements_max: 678888 kstat.zfs.misc.arcstats.hash_collisions: 21697862 kstat.zfs.misc.arcstats.hash_chains: 182323 kstat.zfs.misc.arcstats.hash_chain_max: 9 kstat.zfs.misc.arcstats.p: 1251375616 kstat.zfs.misc.arcstats.c: 1252817408 kstat.zfs.misc.arcstats.c_min: 1252817408 kstat.zfs.misc.arcstats.c_max: 10022539264 kstat.zfs.misc.arcstats.size: 1237578176 kstat.zfs.misc.arcstats.hdr_size: 9610640 kstat.zfs.misc.arcstats.l2_hits: 12905801 kstat.zfs.misc.arcstats.l2_misses: 680 kstat.zfs.misc.arcstats.l2_feeds: 52666 kstat.zfs.misc.arcstats.l2_rw_clash: 680 kstat.zfs.misc.arcstats.l2_writes_sent: 41330 kstat.zfs.misc.arcstats.l2_writes_done: 41330 kstat.zfs.misc.arcstats.l2_writes_error: 0 kstat.zfs.misc.arcstats.l2_writes_hdr_miss: 62 kstat.zfs.misc.arcstats.l2_evict_lock_retry: 53 kstat.zfs.misc.arcstats.l2_evict_reading: 5 kstat.zfs.misc.arcstats.l2_free_on_write: 30044 kstat.zfs.misc.arcstats.l2_abort_lowmem: 309837 kstat.zfs.misc.arcstats.l2_cksum_bad: 0 kstat.zfs.misc.arcstats.l2_io_error: 0 kstat.zfs.misc.arcstats.l2_size: 79319831552 kstat.zfs.misc.arcstats.l2_hdr_size: 134102528 kstat.zfs.misc.arcstats.memory_throttle_count: 112340 kstat.zfs.misc.vdev_cache_stats.delegations: 3822 kstat.zfs.misc.vdev_cache_stats.hits: 342974 kstat.zfs.misc.vdev_cache_stats.misses: 170601 WBR, Alexander Shevchenko
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