On Fri, Jul 23, 2021 at 08:10:28PM +0000, Andy Smith wrote:
> Hmm, I have the sector offset in the MD device so maybe I can
> convert that into a logical volume to know if a particular guest is
> provoking it…
So for anyone who ever wants to do that sort of thing:
# Find out offset that LVM puts LVs from start of its physical
# device
$ sudo pvs --noheadings -o pe_start --units s /dev/md4
2048S
# Find out the sector size of each LVM extent (PE)
$ sudo pvdisplay --units s /dev/md4 | grep 'PE Size'
PE Size 8192 Se
# Report PE number for each sector
$ for sect in 912000815 916064223 1934755601 914360207 1936852857; do
lv_sect=$((sect-2048)); pe=$((sect / 8192)); printf "%s: sector %s PE %s\n"
$sect $lv_sect $pe; done
912000815: sector 911998767 PE 111328
916064223: sector 916062175 PE 111824
1934755601: sector 1934753553 PE 236176
914360207: sector 914358159 PE 111616
1936852857: sector 1936850809 PE 236432
Looking the PE numbers up in the output of "pvdisplay --maps --units
s /dev/md4" I can see it's three hits for one guest and two for
another.
I will see if I can move the 3 time affected guest to test hardware.
Cheers,
Andy
