As suggested, I added the package for /bin/lsblk. That is probably good
enough for initial bug report.
Dusan Baljevic
** Package changed: ubuntu = util-linux (Ubuntu)
--
You received this bug notification because you are a member of Ubuntu
Touch seeded packages, which is subscribed to util-linux in Ubuntu.
https://bugs.launchpad.net/bugs/1346687
Title:
Ubuntu 14 KVM Guest I/O Elevator Non-configurable
Status in “util-linux” package in Ubuntu:
New
Bug description:
Ubuntu 14.04 guest runs pretty much standard standard configuration:
KVM hypervisor, ACPI and APIC enabled, virtio disk bus, raw storage
format...
While running this project, I am also involved in testing SSD drives
across different Linux distributions and their support for discard
option (TRIM).
To cut the story short, Ubuntu-based KVM guest did not set any
scheduler on the boot disk vda):
# lsblk -io KNAME,TYPE,SCHED,ROTA,DISC-GRAN,DISC-MAX
KNAME TYPE SCHED ROTA DISC-GRAN DISC-MAX
sr0 rom deadline 1 0B 0B
vda disk 1 0B 0B
vda1 part 1 0B 0B
vda2 part 1 0B 0B
vda5 part 1 0B 0B
dm-0 lvm 1 0B 0B
dm-1 lvm 1 0B 0B
That is in stark contrast with other distributions running almost
identical KVM guest configuration (with the exception of the root file
system using BTRFS instead of EXT4 on SUSE).
Oracle Linux 6.5:
# lsblk -io KNAME,TYPE,SCHED,ROTA,DISC-GRAN,DISC-MAX
KNAME TYPE SCHED ROTA DISC-GRAN DISC-MAX
sr0 rom deadline 1 0B 0B
vda disk deadline 1 0B 0B
vda1 part deadline 1 0B 0B
vda2 part deadline 1 0B 0B
dm-0 lvm 1 0B 0B
dm-1 lvm 1 0B 0B
OpenSUSE 13.1:
# lsblk -io KNAME,TYPE,SCHED,ROTA,DISC-GRAN,DISC-MAX
KNAME TYPE SCHED ROTA DISC-GRAN DISC-MAX
sr0 rom cfq 1 0B 0B
vda disk cfq 1 0B 0B
vda1 part cfq 1 0B 0B
vda2 part cfq 1 0B 0B
dm-0 lvm 1 0B 0B
dm-1 lvm 1 0B 0B
Indeed, checking elevator capabilities for boot disk on Ubuntu KVM
guest showed:
# cat /sys/block/vda/queue/scheduler
none
Other Linux distributions show more options:
# cat /sys/block/vda/queue/scheduler
noop deadline [cfq]
As well, attempts to change the elevator on Ubuntu guest fail. For
example:
# echo noop /sys/block/vda/queue/scheduler
# echo $?
0
# cat /sys/block/vda/queue/scheduler
none
Setting it globally in /etc/default/grub and updating it via update-
grub2 fails too.
In the meantime, to automate check of elevators (schedulers) and
discard support for SSD drives and thin-provisioned volumes on Linux,
I wrote simple Perl script:
http://www.circlingcycle.com.au/Unix-sources/Linux-check-IO-scheduler-
and-discard-support.pl.txt
Part of the results on RHEL 6.5 server would look like:
INFO: I/O elevator (scheduler) and discard support summary
INFO: Hard Disk sdb configured with I/O scheduler cfq
INFO: SSD sda configured with I/O scheduler deadline supports discard
operation
INFO: Hard Disk sdc configured with I/O scheduler cfq
INFO: Hard Disk sdi configured with I/O scheduler cfq
INFO: Hard Disk sdh configured with I/O scheduler cfq
The Ubuntu KVM guest runs latest paches:
Linux ubuntu14-vm2.circlingcycle.com.au 3.13.0-24-generic
#47-Ubuntu SMP Fri May 2 23:30:00 UTC 2014 x86_64 x86_64 x86_64 GNU/Linux
Regards,
Dusan Baljevic VK2COT
To manage notifications about this bug go to:
https://bugs.launchpad.net/ubuntu/+source/util-linux/+bug/1346687/+subscriptions
--
Mailing list: https://launchpad.net/~touch-packages
Post to : touch-packages@lists.launchpad.net
Unsubscribe : https://launchpad.net/~touch-packages
More help : https://help.launchpad.net/ListHelp
