[Bug 1057054] Re: poor performance after upgrade to Precise
peter.petrakis at canonical.com
Thu Sep 27 04:16:58 UTC 2012
Then we might have a distro bug here, which is weird as I've done hundreds of
SAN installs with lucid and have had to manage the scsi_dh modules everytime.
So on your lucid system, /etc/initramfs-tools/modules should be empty
except for the commented out examples.
The next thing to check is the initram disks themselves, assuming there's no
directives in the previous config file, the presence of the scsi_dh kos in
the initrd would indicate that they were be globbed in by another
root at nashira:~# zcat /boot/initrd.img-3.2.0-26-generic | cpio -it | grep scsi_dh
root at nashira:~# zcat /boot/initrd.img-2.6.32-41-generic | cpio -it | grep scsi_dh
OK, I'm surprised :)
In my 2.6.32 initrd I find:
root at nashira:~/2.6.32# cat conf/modules
which I suppose prompts my device handler to be installed. Which is driven
by 'modules' and 'modules.d' in /usr/share/initramfs-tools. So the modules
apparently have always been there, thanks to this hook script.
for x in mptfc mptsas mptscsih mptspi zfcp; do
Which is how the scsi_dh_* kos got on the initramfs, but that doesn't
explain how it was loaded. That directive had to come from somewhere,
so it's either already in your /usr/share/initramfs-tools/modules|modules.d
or it's in your /etc/initramfs-tools/modules.d|modules and you missed it.
*something* has to be prompting it's inclusion.
What's the output of, as root?
grep -Rl scsi_dh /etc /usr/share/initramfs-tools/
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poor performance after upgrade to Precise
Status in “multipath-tools” package in Ubuntu:
I had a Lucid x64 server working with a Dell MD3000i with 4 paths and
worked as expected. I added the "prio rdac" line to the conf file,
then upgraded to Precise, and removed the old mpath_rdac line and
reboot one more time, just to be sure. I did this based on a section
as a "sanity check" test, I'm doing 'pv < /dev/mapper/dellsas1 >
/dev/null' (friendly names enabled). On Lucid i'd get about 100MB/s
After upgrading to Precise I get an almost solid 768kB/s. If I
instead use the 4 underlying /dev/sd* devices, 2 give errors as
expected, and 2 run at about 100MB/s as expected so iscsi seems to be
working correctly and multipath not.
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