On Fri, Sep 21, 2018 at 7:19 AM Xiao Ni <xni@xxxxxxxxxx> wrote: > > > > ----- Original Message ----- > > From: "Guoqing Jiang" <gqjiang@xxxxxxxx> > > To: "Gi-Oh Kim" <gi-oh.kim@xxxxxxxxxxxxxxxx>, "Shaohua Li" <shli@xxxxxx>, "NeilBrown" <neilb@xxxxxxx> > > Cc: "Jinpu Wang" <jinpu.wang@xxxxxxxxxxxxxxxx>, linux-raid@xxxxxxxxxxxxxxx > > Sent: Friday, September 21, 2018 11:57:50 AM > > Subject: Re: [RFC] wrong behavior of re-adding a device > > > > > > > > On 9/20/18 9:36 PM, Gi-Oh Kim wrote: > > > On Wed, Sep 19, 2018 at 5:09 PM Gi-Oh Kim <gi-oh.kim@xxxxxxxxxxxxxxxx> > > > wrote: > > >> Hi, > > >> > > >> I found a weird behavior of re-adding a device. > > >> I think it is a kernel bug. > > >> I would appreciate it if somebody can confirm if it is a bug or feature. > > >> > > >> I tested re-adding a device as following. > > >> 1. create md with ram0 and ram1 > > >> 2. add ram2 > > >> 3. grow raid-device number to 3 > > >> 4. remove ram2 > > >> 5. grow raid-device number to 2 > > >> 6. add ram2 > > >> 7. ram0 become faulty and ram2 become active > > >> 8. stop md > > >> 9. assemble md with ram0 and ram1 => fail because ram0 is faulty > > Hi Gi > > I haven't reproduce your problem. Are there something wrong with the steps? > > [root@dell-per230-03 home]# uname -r > 4.19.0-rc4 > > > [root@dell-per230-03 home]# modprobe brd rd_nr=4 rd_size=12582912 > [root@dell-per230-03 home]# ls /dev/ram* > /dev/ram0 /dev/ram1 /dev/ram2 /dev/ram3 > [root@dell-per230-03 home]# mdadm -CR /dev/md0 -l1 -n2 /dev/ram0 /dev/ram1 > [root@dell-per230-03 home]# mdadm /dev/md0 -a /dev/ram2 > mdadm: added /dev/ram2 > [root@dell-per230-03 home]# cat /proc/mdstat > Personalities : [raid1] > md0 : active raid1 ram2[2](S) ram1[1] ram0[0] > 12573696 blocks super 1.2 [2/2] [UU] > [root@dell-per230-03 home]# mdadm /dev/md0 --grow --raid-device=3 > raid_disks for /dev/md0 set to 3 > [root@dell-per230-03 home]# cat /proc/mdstat > Personalities : [raid1] > md0 : active raid1 ram2[2] ram1[1] ram0[0] > 12573696 blocks super 1.2 [3/3] [UUU] > > unused devices: <none> > [root@dell-per230-03 home]# mdadm /dev/md0 -f /dev/ram2 > mdadm: set /dev/ram2 faulty in /dev/md0 > [root@dell-per230-03 home]# mdadm /dev/md0 -r /dev/ram2 > mdadm: hot removed /dev/ram2 from /dev/md0 > [root@dell-per230-03 home]# cat /proc/mdstat > Personalities : [raid1] > md0 : active raid1 ram1[1] ram0[0] > 12573696 blocks super 1.2 [3/2] [UU_] > > unused devices: <none> > [root@dell-per230-03 home]# mdadm /dev/md0 --grow --raid-devices=2 > raid_disks for /dev/md0 set to 2 > [root@dell-per230-03 home]# cat /proc/mdstat > Personalities : [raid1] > md0 : active raid1 ram1[1] ram0[0] > 12573696 blocks super 1.2 [2/2] [UU] > > unused devices: <none> > [root@dell-per230-03 home]# mdadm /dev/md0 -a /dev/ram2 > mdadm: added /dev/ram2 Hi Xiao, Your mdadm shows "added" but my mdadm shows "re-added". I think "re-add" is what cause the problem. Could you try "mdadm /dev/md0 --re-add /dev/ram2"? > [root@dell-per230-03 home]# cat /proc/mdstat > Personalities : [raid1] > md0 : active raid1 ram2[2](S) ram1[1] ram0[0] > 12573696 blocks super 1.2 [2/2] [UU] > > unused devices: <none> > > Regards > Xiao -- GIOH KIM Linux Kernel Entwickler ProfitBricks GmbH Greifswalder Str. 207 D - 10405 Berlin Tel: +49 176 2697 8962 Fax: +49 30 577 008 299 Email: gi-oh.kim@xxxxxxxxxxxxxxxx URL: https://www.profitbricks.de Sitz der Gesellschaft: Berlin Registergericht: Amtsgericht Charlottenburg, HRB 125506 B Geschäftsführer: Achim Weiss, Matthias Steinberg, Christoph Steffens
