Improving ZFS performance for large directories

[Kevin Day]

On Jan 30, 2013, at 10:34 AM, Nikolay Denev <ndenev at gmail.com> wrote:

>> 
>> vfs.zfs.arc_meta_limit: 8199079936
>> vfs.zfs.arc_meta_used: 13965744408
>> 
>> Full output of zfs-stats: […snipped…]
> 
> Looks like you can try to increase arc_meta_limit to be let's say : half of arc_max. (16398159872 in your case).
> 
> 

Okay, will give this a shot on the next reboot too.

Does anyone here understand the significance of "used" being higher than "limit"? Is the limit only a suggestion, or are there cases where there'a certain metadata that must be in arc, and it's particularly large here?

-- Kevin