Bug 1475780
| Summary: | [RFE][scale] - Set "blkdiscard" as the default zero method | ||
|---|---|---|---|
| Product: | [oVirt] vdsm | Reporter: | Idan Shaby <ishaby> |
| Component: | RFEs | Assignee: | Idan Shaby <ishaby> |
| Status: | CLOSED CURRENTRELEASE | QA Contact: | Kevin Alon Goldblatt <kgoldbla> |
| Severity: | medium | Docs Contact: | |
| Priority: | low | ||
| Version: | 4.18.15 | CC: | amureini, bugs, ebenahar, ishaby, ratamir, tnisan, trichard, ykaul, ylavi |
| Target Milestone: | ovirt-4.2.2 | Keywords: | FutureFeature, Performance |
| Target Release: | --- | Flags: | tnisan:
ovirt-4.2?
tnisan: exception? ratamir: testing_plan_complete- rule-engine: planning_ack? rule-engine: devel_ack+ rule-engine: testing_ack+ |
| Hardware: | Unspecified | ||
| OS: | Unspecified | ||
| Whiteboard: | |||
| Fixed In Version: | Doc Type: | Enhancement | |
| Doc Text: |
The default zeroing method has been changed from "dd" to "blkdiscard". The new default method performs significantly better than "dd", as it can use storage offloading (if it is supported by the storage array), and it consumes much less network bandwidth. If required, it is possible to locally set the zeroing method back to "dd" by changing the "zero_method" parameter in /etc/vdsm/vdsm.conf to "dd".
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Story Points: | --- |
| Clone Of: | 1367806 | Environment: | |
| Last Closed: | 2018-03-29 11:03:36 UTC | Type: | Bug |
| Regression: | --- | Mount Type: | --- |
| Documentation: | --- | CRM: | |
| Verified Versions: | Category: | --- | |
| oVirt Team: | Storage | RHEL 7.3 requirements from Atomic Host: | |
| Cloudforms Team: | --- | Target Upstream Version: | |
| Embargoed: | |||
| Bug Depends On: | 1327886, 1367806 | ||
| Bug Blocks: | 872530, 1314382 | ||
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Comment 1
Yaniv Kaul
2017-07-30 08:49:07 UTC
Yes, but since we're talking about the config value "zero_method" (see Bug 1367806), the option name is "blkdiscard". I will open a new BZ to track the second RFE you implied to, i.e when the user removes a disk with an intention to zero and discard it, and the underlying storage support discard_zeroes_data, then the disk is only discarded (and not wiped). This depends on the scale's team ability to prove this method is safe. Verified with the following code: ---------------------------------------- ovirt-engine-4.2.2.5-0.1.el7.noarch vdsm-4.20.23-1.el7ev.x86_64 Verified with the following scenario: ---------------------------------------- 1. Created a VM with 10G iscsi disk 2. Started the VM and wrote a 3G of data to the disk 3. Stop the VM 4. Remove the disk 5. Calculated the time that passes between the log message "Zero volume thread started for volume <volume_id>" and the log message "Zero volume <volume_id> task <task_id> completed" >>>>> 4 seconds passed. Moving to VERIFIED This bugzilla is included in oVirt 4.2.2 release, published on March 28th 2018. Since the problem described in this bug report should be resolved in oVirt 4.2.2 release, it has been closed with a resolution of CURRENT RELEASE. If the solution does not work for you, please open a new bug report. |