Re: --bitmap=lockless across server reboot

"Yu Kuai" <[email protected]>
Newsgroups gmane.linux.raid
Message-ID <[email protected]>
Hi,

在 2026/5/25 23:08, Anton Gavriliuk 写道:
> Hhmm.... I just re-checked it with latest kernel (7.1-rc5) on Fedora
> Server 44, and now it works, log below.  I don't remember on which
> kernel I saw that issue (7.1-rc3 or 7.1-rc4)

If the latest kernel works well, then it's fine. llbitmap is still
under experimental stage, and there will be patches for bug fix and
features.

>
> BTW, earlier you mentioned that you are working on raid5 performance
> improvements,
>
> "“BTW we're working on performance
> improvement for large raid5 arrays for at most 64 disks, results looks great.
> However, it might take sometime before we push our work to upstream.”
>
> Are there any progress ?, I'm very interested to test on PCIe 5.0 NVMe drives.

Yes, but we'll keep those improvements downstream for sometime. We have plans
to push them to upstream but it'll wait for about 1 or 2 years :)

>
> This is Fedora Server 44 (up to date) with compiled kernel 7.1-rc5
>
> [root@qdevice ~]# cat /etc/*release
> Fedora release 44 (Forty Four)
> NAME="Fedora Linux"
> VERSION="44 (Server Edition)"
> RELEASE_TYPE=stable
> ID=fedora
> VERSION_ID=44
> VERSION_CODENAME=""
> PRETTY_NAME="Fedora Linux 44 (Server Edition)"
> ANSI_COLOR="0;38;2;60;110;180"
> LOGO=fedora-logo-icon
> CPE_NAME="cpe:/o:fedoraproject:fedora:44"
> HOME_URL="https://fedoraproject.org/"
> DOCUMENTATION_URL="https://docs.fedoraproject.org/en-US/fedora/f44/"
> SUPPORT_URL="https://ask.fedoraproject.org/"
> BUG_REPORT_URL="https://bugzilla.redhat.com/"
> REDHAT_BUGZILLA_PRODUCT="Fedora"
> REDHAT_BUGZILLA_PRODUCT_VERSION=44
> REDHAT_SUPPORT_PRODUCT="Fedora"
> REDHAT_SUPPORT_PRODUCT_VERSION=44
> SUPPORT_END=2027-05-19
> VARIANT="Server Edition"
> VARIANT_ID=server
> Fedora release 44 (Forty Four)
> Fedora release 44 (Forty Four)
> [root@qdevice ~]#
> [root@qdevice ~]# uname -a
> Linux qdevice 7.1.0-rc5 #1 SMP PREEMPT_DYNAMIC Mon May 25 15:02:20
> EEST 2026 x86_64 GNU/Linux
> [root@qdevice ~]#
> [root@qdevice mdadm]# lsblk
> NAME        MAJ:MIN RM   SIZE RO TYPE MOUNTPOINTS
> nvme6n1     259:1    0 447.1G  0 disk
> ├─nvme6n1p1 259:2    0     1G  0 part /boot/efi
> ├─nvme6n1p2 259:3    0     1G  0 part /boot
> ├─nvme6n1p3 259:4    0   220G  0 part /
> ├─nvme6n1p4 259:5    0     1G  0 part
> └─nvme6n1p5 259:6    0   220G  0 part
> nvme3n1     259:10   0   2.9T  0 disk
> nvme1n1     259:11   0   2.9T  0 disk
> nvme0n1     259:12   0   2.9T  0 disk
> nvme4n1     259:16   0   2.9T  0 disk
> nvme2n1     259:17   0   2.9T  0 disk
> nvme5n1     259:18   0   2.9T  0 disk
> [root@qdevice mdadm]#
> [root@qdevice mdadm]# mdadm --create --verbose /dev/md0 --level=6
> --bitmap=lockless --raid-devices=6 /dev/nvme0n1 /dev/nvme1n1
> /dev/nvme2n1 /dev/nvme3n1 /dev/nvme4n1 /dev/nvme5n1
> mdadm: Experimental lockless bitmap, use at your own risk!
> mdadm: layout defaults to left-symmetric
> mdadm: layout defaults to left-symmetric
> mdadm: chunk size defaults to 512K
> mdadm: /dev/nvme0n1 appears to be part of a raid array:
>         level=raid6 devices=5 ctime=Wed May 20 12:45:26 2026
> mdadm: /dev/nvme1n1 appears to be part of a raid array:
>         level=raid6 devices=5 ctime=Wed May 20 12:45:26 2026
> mdadm: /dev/nvme2n1 appears to be part of a raid array:
>         level=raid6 devices=5 ctime=Wed May 20 12:45:26 2026
> mdadm: /dev/nvme3n1 appears to be part of a raid array:
>         level=raid6 devices=5 ctime=Wed May 20 12:45:26 2026
> mdadm: /dev/nvme4n1 appears to be part of a raid array:
>         level=raid6 devices=5 ctime=Wed May 20 12:45:26 2026
> mdadm: /dev/nvme5n1 appears to be part of a raid array:
>         level=raid6 devices=6 ctime=Wed May 20 11:45:38 2026
> mdadm: size set to 3125484544K
> Continue creating array [y/N]? y
> mdadm: Defaulting to version 1.2 metadata
> mdadm: array /dev/md0 started.
> [root@qdevice mdadm]#
> [root@qdevice mdadm]# lsblk
> NAME        MAJ:MIN RM   SIZE RO TYPE  MOUNTPOINTS
> nvme6n1     259:1    0 447.1G  0 disk
> ├─nvme6n1p1 259:2    0     1G  0 part  /boot/efi
> ├─nvme6n1p2 259:3    0     1G  0 part  /boot
> ├─nvme6n1p3 259:4    0   220G  0 part  /
> ├─nvme6n1p4 259:5    0     1G  0 part
> └─nvme6n1p5 259:6    0   220G  0 part
> nvme3n1     259:10   0   2.9T  0 disk
> └─md0         9:0    0  11.6T  0 raid6
> nvme1n1     259:11   0   2.9T  0 disk
> └─md0         9:0    0  11.6T  0 raid6
> nvme0n1     259:12   0   2.9T  0 disk
> └─md0         9:0    0  11.6T  0 raid6
> nvme4n1     259:16   0   2.9T  0 disk
> └─md0         9:0    0  11.6T  0 raid6
> nvme2n1     259:17   0   2.9T  0 disk
> └─md0         9:0    0  11.6T  0 raid6
> nvme5n1     259:18   0   2.9T  0 disk
> └─md0         9:0    0  11.6T  0 raid6
> [root@qdevice mdadm]#
> [root@qdevice mdadm]# reboot
> [root@qdevice mdadm]#
>
> After reboot,
>
> [root@qdevice ~]# lsblk
> NAME        MAJ:MIN RM   SIZE RO TYPE  MOUNTPOINTS
> nvme6n1     259:1    0 447.1G  0 disk
> ├─nvme6n1p1 259:2    0     1G  0 part  /boot/efi
> ├─nvme6n1p2 259:3    0     1G  0 part  /boot
> ├─nvme6n1p3 259:4    0   220G  0 part  /
> ├─nvme6n1p4 259:5    0     1G  0 part
> └─nvme6n1p5 259:6    0   220G  0 part
> nvme2n1     259:9    0   2.9T  0 disk
> └─md0         9:0    0  11.6T  0 raid6
> nvme1n1     259:10   0   2.9T  0 disk
> └─md0         9:0    0  11.6T  0 raid6
> nvme4n1     259:15   0   2.9T  0 disk
> └─md0         9:0    0  11.6T  0 raid6
> nvme0n1     259:16   0   2.9T  0 disk
> └─md0         9:0    0  11.6T  0 raid6
> nvme3n1     259:17   0   2.9T  0 disk
> └─md0         9:0    0  11.6T  0 raid6
> nvme5n1     259:18   0   2.9T  0 disk
> └─md0         9:0    0  11.6T  0 raid6
> [root@qdevice ~]#
>
>
> Anton
>
> пн, 25 мая 2026 г. в 08:32, Yu Kuai <[email protected]>:
>> Hi,
>>
>> 在 2026/5/20 1:28, Anton Gavriliuk 写道:
>>> Hi
>>>
>>> Does md-raid lockless bitmap support server's reboot ?
>> Yes, of course it should support reboot.
>>
>>> I don't see md-raid6 created with --bitmap=lockless after reboot.
>> Do you check kernel log if there is any failure log? And do you try
>> mdadm -a manually?
>>
>> BTW, pPlease report with your environment and test script in details,
>> especially kernel version and mdadm version.
>>
>>> Anton
>>>
>> --
>> Thansk,
>> Kuai

-- 
Thansk,
Kuai
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