[dm-devel] good nb io setting (was multipath timing help sought)

["Kevin Foote" <kevin foote gmail com>]

OK so looking back through the docs etc I have some what answered my own question. my rr_min_io values is pretty out of the ordinary
from reading through things. Also I could adjust the polling_interval back to the default of 5

my multipath.conf default looks like (as mentioned before) this:
========= /etc/multipath.conf ================
defaults {
        multipath_tool          "/sbin/multipath -v0"
        udev_dir                /dev
        polling_interval        2
        selector                "round-robin 0"
        path_grouping_policy    failover
        getuid_callout          "/sbin/scsi_id -g -u -s /block/%n"
        path_checker            readsector0
        prio_callout            "/bin/true"
        features                "0"
        rr_min_io               2                                        
        rr_weight               priorities
        failback                immediate
        no_path_retry           fail
        user_friendly_name      yes
}
========= ============= ================

I do not replace the rr_min_io value within my multipath device sections so a map looks like this when complete.

   0 33576960 multipath 0 0 2 1 round-robin 0 1 1 8:80 2 round-robin 0 1 1 8:176 2
                                                                                 ^
                                                                                 |_ this value is way off from the default of 1000 

I know this is a highly user specific value however do most people stay around the default value for this setting. 
Specifically I'm looking for input on an io value for db volumes.  

Also would all this be a non issue if I set rr_weight to uniform instead of priorities ( which I  think evals to (0*2) in my case ).
Any help appreciated.. 

-- 
:wq!
kevin.foote