Feature #3053
Multi-Queue virtio-scsi
| Status: | Closed | Start date: | 07/16/2014 | |
|---|---|---|---|---|
| Priority: | Normal | Due date: | ||
| Assignee: |  Javi Fontan | % Done: | 0% | |
| Category: | Drivers - VM | |||
| Target version: | Release 5.4 | |||
| Resolution: | fixed | Pull request: |
Description
Multi-queue virtio-scsi provides improved storage performance and scalability in the virtio-scsi driver. It enables each virtual CPU to have a separate queue and interrupt to use without affecting other vCPUs.
Multi-queue virtio-scsi is disabled by default on Red Hat Enterprise Linux 7.
To enable multi-queue virtio-scsi support in the guest, add the following to the guest XML configuration, where N is the total number of vCPU queues:
<controller type='scsi' index='0' model='virtio-scsi'>
<driver queues='N' />
</controller>Related issues
Associated revisions
F #3053: Add support for virtio-scsi controller
F #3053: add virtio_scsi to defaults file
F #3053: add virtio-scsi controller when queues are specified
F #3053: add explicit address to scsi drives
By default scsi drives increase the unit part of the address. This
causes problems in linux as the devices are not created in order.
Setting the target forces the order to be maintained.
F #3053 Added virtio-scsi Queues input in OS Booting (update VM Template)
History
#1
Updated by 海涛 肖 almost 7 years ago
XML example:
<controller type='scsi' index='0' model='virtio-scsi'>
<driver queues='N' />
</controller>
#2
Updated by Florian Heigl about 4 years ago
Could someone look at this? it has major performance impact and virtio-scsi is also needed for trim to work as far as I know. (I can set "unmap" now but not sure that'd be enough)
#3
Updated by Javi Fontan about 4 years ago
You can enable virtio-scsi adding this RAW parameter to the template or to defaults kvm driver file:
RAW=[ DATA="<devices><controller type='scsi' index='0' model='virtio-scsi'></controller></devices>", TYPE="kvm" ]
You can add the disks in SCSI bus and use trim.
#4
Updated by Javi Fontan about 4 years ago
- Category set to Drivers - VM
- Assignee set to Javi Fontan
- Target version set to Release 5.4
#5
Updated by Javi Fontan about 4 years ago
- Tracker changed from Request to Feature
- Status changed from Pending to Closed
- Resolution set to fixed
libvirt already adds a virtio-scsi controller if there is none and a scsi disk is added. There's a new option to specify the number of queues:
FEATURES = [ VIRTIO_SCSI_QUEUES = 4 ]
If this parameter is specified and greater than 0 a controller is added with that amount of queues.
#6
Updated by Javi Fontan about 4 years ago
- Related to Feature #3060: trim/discard for Ceph RBD added