| Summary: | Use two disks to create raid5 should be failed on cockpit,but it was successfully. | ||||||||||||||
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| Product: | Red Hat Enterprise Linux 7 | Reporter: | Yihui Zhao <yzhao> | ||||||||||||
| Component: | cockpit | Assignee: | Marius Vollmer <mvollmer> | ||||||||||||
| Status: | CLOSED NOTABUG | QA Contact: | qe-baseos-daemons | ||||||||||||
| Severity: | medium | Docs Contact: | |||||||||||||
| Priority: | unspecified | ||||||||||||||
| Version: | 7.2 | CC: | bugs, cshao, danken, fche, fdeutsch, huzhao, jiawu, leiwang, michal.skrivanek, weiwang, yaniwang, ycui, yzhao | ||||||||||||
| Target Milestone: | pre-dev-freeze | Keywords: | Extras | ||||||||||||
| Target Release: | --- | ||||||||||||||
| Hardware: | x86_64 | ||||||||||||||
| OS: | Linux | ||||||||||||||
| Whiteboard: | |||||||||||||||
| Fixed In Version: | Doc Type: | If docs needed, set a value | |||||||||||||
| Doc Text: | Story Points: | --- | |||||||||||||
| Clone Of: | Environment: | ||||||||||||||
| Last Closed: | 2016-09-20 14:21:17 UTC | Type: | Bug | ||||||||||||
| Regression: | --- | Mount Type: | --- | ||||||||||||
| Documentation: | --- | CRM: | |||||||||||||
| Verified Versions: | Category: | --- | |||||||||||||
| oVirt Team: | --- | RHEL 7.3 requirements from Atomic Host: | |||||||||||||
| Cloudforms Team: | --- | Target Upstream Version: | |||||||||||||
| Bug Depends On: | |||||||||||||||
| Bug Blocks: | 1329957 | ||||||||||||||
| Attachments: |
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Target release should be placed once a package build is known to fix a issue. Since this bug is not modified, the target version has been reset. Please use target milestone to plan a fix for a oVirt release. Created attachment 1192773 [details]
two_disks_raid5_failed.png
Created attachment 1192774 [details]
two_disks_raid5_cockpit1.png
Created attachment 1192775 [details]
two_disks_raid5_cockpit2.png
Created attachment 1192776 [details]
ks file
Maybe this should even go to storaged .. The mdraid subsystem allows creating raid level 5 devices with only two disks. It might be a bad idea, but it can be done. I think it treats it as a three-drive array where one drive has failed. We might want to warn against this use, of course. I'll ask around for more input. > I think it treats it as a three-drive array where one drive has failed.
When run manually:
# dd if=/dev/zero of=DISK2 bs=1048576 count=128
# dd if=/dev/zero of=DISK1 bs=1048576 count=128
# losetup DISK2
# losetup DISK1
# mdadm --create /dev/md/test -l 5 --raid-disks 2 /dev/loop0 /dev/loop1
results in a md with 128mb capacity, so a happy redundant raid5, basically equivalent to raid1 mirror.
(In reply to Frank Ch. Eigler from comment #9) > > I think it treats it as a three-drive array where one drive has failed. > > When run manually: > > # dd if=/dev/zero of=DISK2 bs=1048576 count=128 > # dd if=/dev/zero of=DISK1 bs=1048576 count=128 > # losetup DISK2 > # losetup DISK1 > # mdadm --create /dev/md/test -l 5 --raid-disks 2 /dev/loop0 /dev/loop1 > > results in a md with 128mb capacity, so a happy redundant raid5, basically > equivalent to raid1 mirror. Thanks. Let's keep this as a feature then. |
Created attachment 1192772 [details] three_disks_raid5_success.png Description of problem: Use two disks to create raid5 successfully on Cockpit about RHVH4.0. But in fact,we can create raid5 with at least three disks. Version-Release number of selected component (if applicable): redhat-virtualization-host-4.0-20160817.0 cockpit-0.114-2.el7.x86_64 cockpit-ovirt-dashboard-0.10.6-1.3.6.el7ev.noarch How reproducible: 100% Steps to Reproduce: 1.Install NGN4.0 2.Run cockpit client in Firefox/chrome(ip:9090) 3.Switch to storage page 4.Create raid5 with two disks 5.For about twenty minutes,it is successful to create raid5. Actual results: Use two disks to create raid5 successfully on Cockpit about RHVH4.0. Expected results: Use two disks to create raid5 failed on Cockpit about RHVH4.0. Also,we can create raid5 with at least three disks.For details,on attachment: two_disks_riad5_cockpit1.png , two_disks_raid5_cockpit2.png , two_disks_raid5_failed.png, three_disks_raid5_success.png Additional info: My testing environment is using two 100G and clean iscsi disks to create raid5 successfully on cockpit.