Prioritize resilvering priority

[Michelle Sullivan]

Gary Palmer wrote:
> On Tue, Jul 21, 2015 at 04:06:05PM -0700, javocado wrote:
>   
>> Hi,
>>
>> How does one go about prioritizing the resilvering process so it does not
>> overwhelm normal disk I/O on a FreeBSD (8.3amd) system?  Further, can this
>> be altered in real time, or do the settings have to be in place prior to
>> the resilvering even starting?
>>     
>
> You don't state, but is this on ZFS?
>
> I assume they're on 8.3 also, but look at settings like
> vfs.zfs.resilver_min_time_ms and vfs.zfs.resilver_delay in sysctl.
> Searching for resilver_min_time_ms and resilver_delay may give
> some hints, e.g. 
>
> http://broken.net/uncategorized/zfs-performance-tuning-for-scrubs-and-resilvers/
>
> does the opposite to what you want, but it should give hints.  Also
>
> https://www.freebsd.org/doc/en_US.ISO8859-1/books/handbook/zfs-advanced.html
>
> I think they're dynamic.  I tuned the scrub settings and they took effect
> immediately.
>
>   
They mostly the settings are dynamic (both the ones you have above are)
... at worst some settings only take effect at boot time, so if you
wanted to change them reboot.  None of the settings have to be made
before resilvering commences (remember that when you reboot, the
resilver stops then is resumed on startup so any 'boot tunables' take
effect)


-- 
Michelle Sullivan
http://www.mhix.org/