Bug 1718818
| Summary: | [RFE] Enhance local disk passthrough | ||
|---|---|---|---|
| Product: | Red Hat Enterprise Virtualization Manager | Reporter: | Michal Skrivanek <michal.skrivanek> |
| Component: | ovirt-engine | Assignee: | Tomasz Barański <tbaransk> |
| Status: | CLOSED ERRATA | QA Contact: | Nisim Simsolo <nsimsolo> |
| Severity: | high | Docs Contact: | |
| Priority: | high | ||
| Version: | 4.3.4 | CC: | areis, bugs, knoel, lsvaty, mavital, mkalinin, mtessun, nashok, nsimsolo, pagranat, pbonzini, rdlugyhe, stefanha, tbaransk |
| Target Milestone: | ovirt-4.4.1 | Keywords: | FutureFeature |
| Target Release: | --- | Flags: | lsvaty:
testing_plan_complete-
|
| Hardware: | x86_64 | ||
| OS: | Linux | ||
| Whiteboard: | |||
| Fixed In Version: | rhv-4.4.0-29 | Doc Type: | Enhancement |
| Doc Text: |
This enhancement enables you to attach a SCSI host device, `scsi_hostdev`, to a virtual machine and specify the optimal driver for the type of SCSI device:
* *scsi_generic*: (Default) Enables the guest operating system to access OS-supported SCSI host devices attached to the host. Use this driver for SCSI media changers that require raw access, such as tape or CD changers.
* *scsi_block*: Similar to *scsi_generic* but better speed and reliability. Use for SCSI disk devices. If trim or discard for the underlying device is desired, and it’s a hard disk, use this driver.
* *scsi_hd*: Provides performance with lowered overhead. Supports large numbers of devices. Uses the standard SCSI device naming scheme. Can be used with aio-native. Use this driver for high-performance SSDs.
* *virtio_blk_pci*: Provides the highest performance without the SCSI overhead. Supports identifying devices by their serial numbers.
|
Story Points: | --- |
| Clone Of: | Environment: | ||
| Last Closed: | 2020-08-04 13:19:31 UTC | Type: | Bug |
| Regression: | --- | Mount Type: | --- |
| Documentation: | --- | CRM: | |
| Verified Versions: | Category: | --- | |
| oVirt Team: | Virt | RHEL 7.3 requirements from Atomic Host: | |
| Cloudforms Team: | --- | Target Upstream Version: | |
| Embargoed: | |||
| Bug Depends On: | 1793550 | ||
| Bug Blocks: | |||
I agree with the plan, it's a good summary of past discussions and BZs. WARN: Bug status (ON_QA) wasn't changed but the folowing should be fixed:
[Found non-acked flags: '{}', ]
For more info please contact: rhv-devops: Bug status (ON_QA) wasn't changed but the folowing should be fixed:
[Found non-acked flags: '{}', ]
For more info please contact: rhv-devops
WARN: Bug status (ON_QA) wasn't changed but the folowing should be fixed:
[Found non-acked flags: '{}', ]
For more info please contact: rhv-devops: Bug status (ON_QA) wasn't changed but the folowing should be fixed:
[Found non-acked flags: '{}', ]
For more info please contact: rhv-devops
WARN: Bug status (ON_QA) wasn't changed but the folowing should be fixed:
[Found non-acked flags: '{}', ]
For more info please contact: rhv-devops: Bug status (ON_QA) wasn't changed but the folowing should be fixed:
[Found non-acked flags: '{}', ]
For more info please contact: rhv-devops
WARN: Bug status (ON_QA) wasn't changed but the folowing should be fixed:
[Found non-acked flags: '{}', ]
For more info please contact: rhv-devops: Bug status (ON_QA) wasn't changed but the folowing should be fixed:
[Found non-acked flags: '{}', ]
For more info please contact: rhv-devops
WARN: Bug status (ON_QA) wasn't changed but the folowing should be fixed:
[Found non-acked flags: '{}', ]
For more info please contact: rhv-devops: Bug status (ON_QA) wasn't changed but the folowing should be fixed:
[Found non-acked flags: '{}', ]
For more info please contact: rhv-devops
Reassigned, see https://bugzilla.redhat.com/show_bug.cgi?id=1793550 Verified: ovirt-engine-4.4.1.7-0.3.el8ev libvirt-daemon-6.0.0-25.module+el8.2.1+7154+47ffd890.x86_64 vdsm-4.40.22-1.el8ev.x86_64 qemu-kvm-4.2.0-28.module+el8.2.1+7211+16dfe810.x86_64 Verification scenario: Polarion test plan added to external trackers. Since the problem described in this bug report should be resolved in a recent advisory, it has been closed with a resolution of ERRATA. For information on the advisory (Important: RHV Manager (ovirt-engine) 4.4 security, bug fix, and enhancement update), and where to find the updated files, follow the link below. If the solution does not work for you, open a new bug report. https://access.redhat.com/errata/RHSA-2020:3247 |
We currently support SCSI Hostdev Passthrough using a scsi-generic driver only <hostdev mode='subsystem' type='scsi' managed='no' rawio='yes'> which doesn't perform that well. We should add scsi-block and scsi-hd and ideally also virtio-blk-pci. - scsi-block has less overhead than scsi-generic with same capabilities. <disk type='block' device='lun' rawio='yes'> we should consider it a default for disk devices and leave scsi-generic for tapes and such. - scsi-hd is a non-passthrough way, suitable for SSDs with higher performance <disk type='block' device='disk'> can use aio-native - virtio-blk-pci would be the most performant way without the SCSI overhead <disk type='block' device='disk'> with <target dev='vda' bus='virtio'/> supports serial number - for completion, there's also the existing PCI Passthrough option suitable for PCI NVMe SSDs As a rule of thumb the performance should follow: SCSI passthrough overhead guest host ---------------------------------------------------------------------- scsi-generic yes higher high scsi-block yes higher low scsi-hd no higher low virtio-blk-pci no lower lower PCI passthrough N/A lower lowest Possible options depend on the kind of the device: - SCSI non-disks can be exposed as passthrough only(scsi-generic) - SCSI disks can be exposed as passthrough(scsi-block since it's superior to scsi-generic and has no disadvantage), as emulated SCSI(scsi-hd), or even as virtio-blk-pci for better performance - PCI non-NVMe devices can be exposed as passthrough only - PCI NVMe devices can be exposed as PCI passthrough, emulated SCSI(scsi-hd) or virtio-blk-pci. They all should honor the iothread setting as well