md disks EXTREMELY slow 12.3-STABLE

From: Karl Denninger <karl_at_denninger.net>
Date: Fri, 04 Mar 2022 16:22:56 UTC 
Not a little slow, RIDICULOUSLY slow.

Crochet uses these.  Since 12.3 the effective I/O rate, which pegs them 
at 100% busy, is in the 50tps (!!) range.  This is a machine with a 
crap-ton of available RAM (over 10Gb) and effectively no swap use, 
running off SSD for the root pool (ZFS.) Load average is 0.3 yet the md0 
drive is pinned at 100% busy with just 50 transactions-per-second!

This used to be fast in 12.2 and before.

Any ideas as to what might have changed that is causing this?

FreeBSD 12.3-STABLE #18 stable/12-n234659-7963d46bb8c-dirty: Wed Dec 29 
10:59:44 EST 2021

-- 
Karl Denninger
karl@denninger.net
/The Market Ticker/
/[S/MIME encrypted email preferred]/