ZFS and large directories - caveat report

[Luiz Otavio O Souza]

On Jul 21, 2011, at 3:48 PM, David P Discher wrote:

> 
> Ivan -
> 
> What's your uptime ?
> Are you using l2 arc ?
> what is the value of 'sysctl kstat.zfs.misc.arcstats.evict_skip' ?
>  is this increasing quickly ?
> 

Don't know about Ivan's case, but mine is definitively increasing it quickly (and i'm not using l2arc):

sysctl kstat.zfs.misc.arcstats.evict_skip                                                                                                                                                                  
kstat.zfs.misc.arcstats.evict_skip: 129995601

And just a few minutes later (while running find on my 4 million files FS):

sysctl kstat.zfs.misc.arcstats.evict_skip
kstat.zfs.misc.arcstats.evict_skip: 130589384

But i guess i need to increase the arc_meta_limit as well:

vfs.zfs.arc_meta_limit: 536870912
vfs.zfs.arc_meta_used: 579461312
kstat.zfs.misc.arcstats.demand_data_hits: 4400985059
kstat.zfs.misc.arcstats.demand_data_misses: 699262
kstat.zfs.misc.arcstats.demand_metadata_hits: 1057208432
kstat.zfs.misc.arcstats.demand_metadata_misses: 32782389
kstat.zfs.misc.arcstats.prefetch_data_hits: 3302738888
kstat.zfs.misc.arcstats.prefetch_data_misses: 225108
kstat.zfs.misc.arcstats.prefetch_metadata_hits: 418744564
kstat.zfs.misc.arcstats.prefetch_metadata_misses: 147815306

kstat.zfs.misc.arcstats.evict_skip: 130781386
kstat.zfs.misc.arcstats.evict_l2_cached: 0
kstat.zfs.misc.arcstats.evict_l2_eligible: 2514187700736
kstat.zfs.misc.arcstats.evict_l2_ineligible: 176966735360


Unfortunately i need to wait a little bit until i can reboot this server with the new sysctl values.

Thanks everyone for the hints so far.

Luiz