* md127 auto created when use "-B" to build a legacy array without superblocks [not found] <795255819.22273230.1441628546245.JavaMail.zimbra@redhat.com> @ 2015-09-07 12:27 ` Yi Zhang 2015-10-02 7:55 ` Neil Brown 0 siblings, 1 reply; 5+ messages in thread From: Yi Zhang @ 2015-09-07 12:27 UTC (permalink / raw) To: NeilBrown; +Cc: linux-raid Hi Neil When testing 00raid1, found the md127 auto created when use "-B" to build a legacy array without superblocks, is it reasonable? pls check below detailed info: + mdadm -CR /dev/md0 --level=raid1 -n3 /dev/loop0 /dev/loop1 /dev/loop2 mdadm: /dev/loop0 appears to contain an ext2fs file system size=58368K mtime=Thu Jan 1 08:00:00 1970 mdadm: Note: this array has metadata at the start and may not be suitable as a boot device. If you plan to store '/boot' on this device please ensure that your boot-loader understands md/v1.x metadata, or use --metadata=0.90 mdadm: /dev/loop1 appears to contain an ext2fs file system size=38912K mtime=Thu Jan 1 08:00:00 1970 mdadm: Defaulting to version 1.2 metadata mdadm: array /dev/md0 started. + mdadm --wait /dev/md0 + cat /proc/mdstat Personalities : [raid6] [raid5] [raid4] [raid1] md0 : active raid1 loop2[2] loop1[1] loop0[0] 19968 blocks super 1.2 [3/3] [UUU] unused devices: <none> + mdadm -S /dev/md0 mdadm: stopped /dev/md0 + mdadm -B /dev/md0 -l raid1 -n2 /dev/loop0 /dev/loop1 mdadm: array /dev/md0 built and started. + sleep 2 + cat /proc/mdstat Personalities : [raid6] [raid5] [raid4] [raid1] md127 : inactive md0[0](S) 19968 blocks super 1.2 md0 : active raid1 loop1[1] loop0[0] 20000 blocks super non-persistent [2/2] [UU] unused devices: <none> [root@dhcp-12-171 bug]# uname -r 4.2.0 [root@dhcp-12-171 bug]# mdadm -D /dev/md0 /dev/md0: Version : Creation Time : Mon Sep 7 20:21:20 2015 Raid Level : raid1 Array Size : 20000 (19.53 MiB 20.48 MB) Used Dev Size : 20000 (19.53 MiB 20.48 MB) Raid Devices : 2 Total Devices : 2 State : clean Active Devices : 2 Working Devices : 2 Failed Devices : 0 Spare Devices : 0 Number Major Minor RaidDevice State 0 7 0 0 active sync /dev/loop0 1 7 1 1 active sync /dev/loop1 [root@dhcp-12-171 bug]# mdadm -D /dev/md127 /dev/md127: Version : 1.2 Raid Level : raid0 Total Devices : 1 Persistence : Superblock is persistent State : inactive Name : dhcp-12-171.nay.redhat.com:0 (local to host dhcp-12-171.nay.redhat.com) UUID : 40ace956:a9dd0793:f4984d2b:8431b92b Events : 17 Number Major Minor RaidDevice - 9 0 - /dev/md0 Best Regards, Yi Zhang ^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: md127 auto created when use "-B" to build a legacy array without superblocks 2015-09-07 12:27 ` md127 auto created when use "-B" to build a legacy array without superblocks Yi Zhang @ 2015-10-02 7:55 ` Neil Brown 2016-01-26 8:24 ` yizhan 0 siblings, 1 reply; 5+ messages in thread From: Neil Brown @ 2015-10-02 7:55 UTC (permalink / raw) To: Yi Zhang; +Cc: linux-raid [-- Attachment #1: Type: text/plain, Size: 3018 bytes --] Yi Zhang <yizhan@redhat.com> writes: > Hi Neil > > When testing 00raid1, found the md127 auto created when use "-B" to build a legacy array without superblocks, is it reasonable? This happens because udev notices a new device has appeared, looks inside it, sees that it could be part of an md array, and so runs "mdadm --incremental" on it. Sometimes we want udev to do that. Sometimes we don't. There is no easy way for udev to know what we want. NeilBrown > pls check below detailed info: > > + mdadm -CR /dev/md0 --level=raid1 -n3 /dev/loop0 /dev/loop1 /dev/loop2 > mdadm: /dev/loop0 appears to contain an ext2fs file system > size=58368K mtime=Thu Jan 1 08:00:00 1970 > mdadm: Note: this array has metadata at the start and > may not be suitable as a boot device. If you plan to > store '/boot' on this device please ensure that > your boot-loader understands md/v1.x metadata, or use > --metadata=0.90 > mdadm: /dev/loop1 appears to contain an ext2fs file system > size=38912K mtime=Thu Jan 1 08:00:00 1970 > mdadm: Defaulting to version 1.2 metadata > mdadm: array /dev/md0 started. > + mdadm --wait /dev/md0 > + cat /proc/mdstat > Personalities : [raid6] [raid5] [raid4] [raid1] > md0 : active raid1 loop2[2] loop1[1] loop0[0] > 19968 blocks super 1.2 [3/3] [UUU] > > unused devices: <none> > + mdadm -S /dev/md0 > mdadm: stopped /dev/md0 > + mdadm -B /dev/md0 -l raid1 -n2 /dev/loop0 /dev/loop1 > mdadm: array /dev/md0 built and started. > + sleep 2 > + cat /proc/mdstat > Personalities : [raid6] [raid5] [raid4] [raid1] > md127 : inactive md0[0](S) > 19968 blocks super 1.2 > > md0 : active raid1 loop1[1] loop0[0] > 20000 blocks super non-persistent [2/2] [UU] > > unused devices: <none> > [root@dhcp-12-171 bug]# uname -r > 4.2.0 > [root@dhcp-12-171 bug]# mdadm -D /dev/md0 > /dev/md0: > Version : > Creation Time : Mon Sep 7 20:21:20 2015 > Raid Level : raid1 > Array Size : 20000 (19.53 MiB 20.48 MB) > Used Dev Size : 20000 (19.53 MiB 20.48 MB) > Raid Devices : 2 > Total Devices : 2 > > State : clean > Active Devices : 2 > Working Devices : 2 > Failed Devices : 0 > Spare Devices : 0 > > Number Major Minor RaidDevice State > 0 7 0 0 active sync /dev/loop0 > 1 7 1 1 active sync /dev/loop1 > [root@dhcp-12-171 bug]# mdadm -D /dev/md127 > /dev/md127: > Version : 1.2 > Raid Level : raid0 > Total Devices : 1 > Persistence : Superblock is persistent > > State : inactive > > Name : dhcp-12-171.nay.redhat.com:0 (local to host dhcp-12-171.nay.redhat.com) > UUID : 40ace956:a9dd0793:f4984d2b:8431b92b > Events : 17 > > Number Major Minor RaidDevice > > - 9 0 - /dev/md0 > > Best Regards, > Yi Zhang [-- Attachment #2: signature.asc --] [-- Type: application/pgp-signature, Size: 818 bytes --] ^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: md127 auto created when use "-B" to build a legacy array without superblocks 2015-10-02 7:55 ` Neil Brown @ 2016-01-26 8:24 ` yizhan 2016-01-26 22:03 ` NeilBrown 0 siblings, 1 reply; 5+ messages in thread From: yizhan @ 2016-01-26 8:24 UTC (permalink / raw) To: Neil Brown; +Cc: linux-raid On 10/02/2015 03:55 PM, Neil Brown wrote: > Yi Zhang <yizhan@redhat.com> writes: > >> Hi Neil >> >> When testing 00raid1, found the md127 auto created when use "-B" to build a legacy array without superblocks, is it reasonable? > This happens because udev notices a new device has appeared, looks > inside it, sees that it could be part of an md array, and so runs > "mdadm --incremental" on it. Hi Neil I tried the mdadm --incremental, but it doesn't work, below is the operation. # mdadm -D /dev/md0 /dev/md0: Version : Creation Time : Tue Jan 26 03:16:17 2016 Raid Level : raid1 Array Size : 2097152 (2.00 GiB 2.15 GB) Used Dev Size : 2097152 (2.00 GiB 2.15 GB) Raid Devices : 2 Total Devices : 2 State : clean Active Devices : 2 Working Devices : 2 Failed Devices : 0 Spare Devices : 0 Number Major Minor RaidDevice State 0 7 0 0 active sync /dev/loop0 1 7 1 1 active sync /dev/loop1 # mdadm -D /dev/md127 /dev/md127: Version : 1.2 Raid Level : raid0 Total Devices : 1 Persistence : Superblock is persistent State : inactive Name : 0 UUID : 13ada118:129135ff:686de7b7:4cb71d6d Events : 17 Number Major Minor RaidDevice - 9 0 - /dev/md0 # mdadm -I /dev/md127 mdadm: /dev/md127 is not part of an md array. # mdadm -I /dev/md0 mdadm: cannot reopen /dev/md0: Device or resource busy. After I stopped md127, the md0 can be used again. Thanks Yi > Sometimes we want udev to do that. Sometimes we don't. > There is no easy way for udev to know what we want. > > NeilBrown > > >> pls check below detailed info: >> >> + mdadm -CR /dev/md0 --level=raid1 -n3 /dev/loop0 /dev/loop1 /dev/loop2 >> mdadm: /dev/loop0 appears to contain an ext2fs file system >> size=58368K mtime=Thu Jan 1 08:00:00 1970 >> mdadm: Note: this array has metadata at the start and >> may not be suitable as a boot device. If you plan to >> store '/boot' on this device please ensure that >> your boot-loader understands md/v1.x metadata, or use >> --metadata=0.90 >> mdadm: /dev/loop1 appears to contain an ext2fs file system >> size=38912K mtime=Thu Jan 1 08:00:00 1970 >> mdadm: Defaulting to version 1.2 metadata >> mdadm: array /dev/md0 started. >> + mdadm --wait /dev/md0 >> + cat /proc/mdstat >> Personalities : [raid6] [raid5] [raid4] [raid1] >> md0 : active raid1 loop2[2] loop1[1] loop0[0] >> 19968 blocks super 1.2 [3/3] [UUU] >> >> unused devices: <none> >> + mdadm -S /dev/md0 >> mdadm: stopped /dev/md0 >> + mdadm -B /dev/md0 -l raid1 -n2 /dev/loop0 /dev/loop1 >> mdadm: array /dev/md0 built and started. >> + sleep 2 >> + cat /proc/mdstat >> Personalities : [raid6] [raid5] [raid4] [raid1] >> md127 : inactive md0[0](S) >> 19968 blocks super 1.2 >> >> md0 : active raid1 loop1[1] loop0[0] >> 20000 blocks super non-persistent [2/2] [UU] >> >> unused devices: <none> >> [root@dhcp-12-171 bug]# uname -r >> 4.2.0 >> [root@dhcp-12-171 bug]# mdadm -D /dev/md0 >> /dev/md0: >> Version : >> Creation Time : Mon Sep 7 20:21:20 2015 >> Raid Level : raid1 >> Array Size : 20000 (19.53 MiB 20.48 MB) >> Used Dev Size : 20000 (19.53 MiB 20.48 MB) >> Raid Devices : 2 >> Total Devices : 2 >> >> State : clean >> Active Devices : 2 >> Working Devices : 2 >> Failed Devices : 0 >> Spare Devices : 0 >> >> Number Major Minor RaidDevice State >> 0 7 0 0 active sync /dev/loop0 >> 1 7 1 1 active sync /dev/loop1 >> [root@dhcp-12-171 bug]# mdadm -D /dev/md127 >> /dev/md127: >> Version : 1.2 >> Raid Level : raid0 >> Total Devices : 1 >> Persistence : Superblock is persistent >> >> State : inactive >> >> Name : dhcp-12-171.nay.redhat.com:0 (local to host dhcp-12-171.nay.redhat.com) >> UUID : 40ace956:a9dd0793:f4984d2b:8431b92b >> Events : 17 >> >> Number Major Minor RaidDevice >> >> - 9 0 - /dev/md0 >> >> Best Regards, >> Yi Zhang ^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: md127 auto created when use "-B" to build a legacy array without superblocks 2016-01-26 8:24 ` yizhan @ 2016-01-26 22:03 ` NeilBrown 2016-01-27 9:18 ` yizhan 0 siblings, 1 reply; 5+ messages in thread From: NeilBrown @ 2016-01-26 22:03 UTC (permalink / raw) To: yizhan; +Cc: linux-raid [-- Attachment #1: Type: text/plain, Size: 4841 bytes --] On Tue, Jan 26 2016, yizhan wrote: > On 10/02/2015 03:55 PM, Neil Brown wrote: >> Yi Zhang <yizhan@redhat.com> writes: >> >>> Hi Neil >>> >>> When testing 00raid1, found the md127 auto created when use "-B" to build a legacy array without superblocks, is it reasonable? >> This happens because udev notices a new device has appeared, looks >> inside it, sees that it could be part of an md array, and so runs >> "mdadm --incremental" on it. > Hi Neil > I tried the mdadm --incremental, but it doesn't work, below is the > operation. > # mdadm -D /dev/md0 > /dev/md0: > Version : > Creation Time : Tue Jan 26 03:16:17 2016 > Raid Level : raid1 > Array Size : 2097152 (2.00 GiB 2.15 GB) > Used Dev Size : 2097152 (2.00 GiB 2.15 GB) > Raid Devices : 2 > Total Devices : 2 > > State : clean > Active Devices : 2 > Working Devices : 2 > Failed Devices : 0 > Spare Devices : 0 > > Number Major Minor RaidDevice State > 0 7 0 0 active sync /dev/loop0 > 1 7 1 1 active sync /dev/loop1 > # mdadm -D /dev/md127 > /dev/md127: > Version : 1.2 > Raid Level : raid0 > Total Devices : 1 > Persistence : Superblock is persistent > > State : inactive > > Name : 0 > UUID : 13ada118:129135ff:686de7b7:4cb71d6d > Events : 17 > > Number Major Minor RaidDevice > > - 9 0 - /dev/md0 > # mdadm -I /dev/md127 > mdadm: /dev/md127 is not part of an md array. > # mdadm -I /dev/md0 > mdadm: cannot reopen /dev/md0: Device or resource busy. > > After I stopped md127, the md0 can be used again. If, after stopping md127, you try mdadm -I /dev/md0 again it will start /dev/md127 again. This is what udev does which causes md127 to appear in the first place. NeilBrown > > Thanks > Yi >> Sometimes we want udev to do that. Sometimes we don't. >> There is no easy way for udev to know what we want. >> >> NeilBrown >> >> >>> pls check below detailed info: >>> >>> + mdadm -CR /dev/md0 --level=raid1 -n3 /dev/loop0 /dev/loop1 /dev/loop2 >>> mdadm: /dev/loop0 appears to contain an ext2fs file system >>> size=58368K mtime=Thu Jan 1 08:00:00 1970 >>> mdadm: Note: this array has metadata at the start and >>> may not be suitable as a boot device. If you plan to >>> store '/boot' on this device please ensure that >>> your boot-loader understands md/v1.x metadata, or use >>> --metadata=0.90 >>> mdadm: /dev/loop1 appears to contain an ext2fs file system >>> size=38912K mtime=Thu Jan 1 08:00:00 1970 >>> mdadm: Defaulting to version 1.2 metadata >>> mdadm: array /dev/md0 started. >>> + mdadm --wait /dev/md0 >>> + cat /proc/mdstat >>> Personalities : [raid6] [raid5] [raid4] [raid1] >>> md0 : active raid1 loop2[2] loop1[1] loop0[0] >>> 19968 blocks super 1.2 [3/3] [UUU] >>> >>> unused devices: <none> >>> + mdadm -S /dev/md0 >>> mdadm: stopped /dev/md0 >>> + mdadm -B /dev/md0 -l raid1 -n2 /dev/loop0 /dev/loop1 >>> mdadm: array /dev/md0 built and started. >>> + sleep 2 >>> + cat /proc/mdstat >>> Personalities : [raid6] [raid5] [raid4] [raid1] >>> md127 : inactive md0[0](S) >>> 19968 blocks super 1.2 >>> >>> md0 : active raid1 loop1[1] loop0[0] >>> 20000 blocks super non-persistent [2/2] [UU] >>> >>> unused devices: <none> >>> [root@dhcp-12-171 bug]# uname -r >>> 4.2.0 >>> [root@dhcp-12-171 bug]# mdadm -D /dev/md0 >>> /dev/md0: >>> Version : >>> Creation Time : Mon Sep 7 20:21:20 2015 >>> Raid Level : raid1 >>> Array Size : 20000 (19.53 MiB 20.48 MB) >>> Used Dev Size : 20000 (19.53 MiB 20.48 MB) >>> Raid Devices : 2 >>> Total Devices : 2 >>> >>> State : clean >>> Active Devices : 2 >>> Working Devices : 2 >>> Failed Devices : 0 >>> Spare Devices : 0 >>> >>> Number Major Minor RaidDevice State >>> 0 7 0 0 active sync /dev/loop0 >>> 1 7 1 1 active sync /dev/loop1 >>> [root@dhcp-12-171 bug]# mdadm -D /dev/md127 >>> /dev/md127: >>> Version : 1.2 >>> Raid Level : raid0 >>> Total Devices : 1 >>> Persistence : Superblock is persistent >>> >>> State : inactive >>> >>> Name : dhcp-12-171.nay.redhat.com:0 (local to host dhcp-12-171.nay.redhat.com) >>> UUID : 40ace956:a9dd0793:f4984d2b:8431b92b >>> Events : 17 >>> >>> Number Major Minor RaidDevice >>> >>> - 9 0 - /dev/md0 >>> >>> Best Regards, >>> Yi Zhang [-- Attachment #2: signature.asc --] [-- Type: application/pgp-signature, Size: 818 bytes --] ^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: md127 auto created when use "-B" to build a legacy array without superblocks 2016-01-26 22:03 ` NeilBrown @ 2016-01-27 9:18 ` yizhan 0 siblings, 0 replies; 5+ messages in thread From: yizhan @ 2016-01-27 9:18 UTC (permalink / raw) To: NeilBrown; +Cc: linux-raid On 01/27/2016 06:03 AM, NeilBrown wrote: > On Tue, Jan 26 2016, yizhan wrote: > >> On 10/02/2015 03:55 PM, Neil Brown wrote: >>> Yi Zhang <yizhan@redhat.com> writes: >>> >>>> Hi Neil >>>> >>>> When testing 00raid1, found the md127 auto created when use "-B" to build a legacy array without superblocks, is it reasonable? >>> This happens because udev notices a new device has appeared, looks >>> inside it, sees that it could be part of an md array, and so runs >>> "mdadm --incremental" on it. >> Hi Neil >> I tried the mdadm --incremental, but it doesn't work, below is the >> operation. >> # mdadm -D /dev/md0 >> /dev/md0: >> Version : >> Creation Time : Tue Jan 26 03:16:17 2016 >> Raid Level : raid1 >> Array Size : 2097152 (2.00 GiB 2.15 GB) >> Used Dev Size : 2097152 (2.00 GiB 2.15 GB) >> Raid Devices : 2 >> Total Devices : 2 >> >> State : clean >> Active Devices : 2 >> Working Devices : 2 >> Failed Devices : 0 >> Spare Devices : 0 >> >> Number Major Minor RaidDevice State >> 0 7 0 0 active sync /dev/loop0 >> 1 7 1 1 active sync /dev/loop1 >> # mdadm -D /dev/md127 >> /dev/md127: >> Version : 1.2 >> Raid Level : raid0 >> Total Devices : 1 >> Persistence : Superblock is persistent >> >> State : inactive >> >> Name : 0 >> UUID : 13ada118:129135ff:686de7b7:4cb71d6d >> Events : 17 >> >> Number Major Minor RaidDevice >> >> - 9 0 - /dev/md0 >> # mdadm -I /dev/md127 >> mdadm: /dev/md127 is not part of an md array. >> # mdadm -I /dev/md0 >> mdadm: cannot reopen /dev/md0: Device or resource busy. >> >> After I stopped md127, the md0 can be used again. > If, after stopping md127, you try > > mdadm -I /dev/md0 > > again it will start /dev/md127 again. This is what udev does which > causes md127 to appear in the first place. > > NeilBrown Thanks Neil I have tried 'mdadm -I /dev/md0', the /dev/md127 start again Yi > >> Thanks >> Yi >>> Sometimes we want udev to do that. Sometimes we don't. >>> There is no easy way for udev to know what we want. >>> >>> NeilBrown >>> >>> >>>> pls check below detailed info: >>>> >>>> + mdadm -CR /dev/md0 --level=raid1 -n3 /dev/loop0 /dev/loop1 /dev/loop2 >>>> mdadm: /dev/loop0 appears to contain an ext2fs file system >>>> size=58368K mtime=Thu Jan 1 08:00:00 1970 >>>> mdadm: Note: this array has metadata at the start and >>>> may not be suitable as a boot device. If you plan to >>>> store '/boot' on this device please ensure that >>>> your boot-loader understands md/v1.x metadata, or use >>>> --metadata=0.90 >>>> mdadm: /dev/loop1 appears to contain an ext2fs file system >>>> size=38912K mtime=Thu Jan 1 08:00:00 1970 >>>> mdadm: Defaulting to version 1.2 metadata >>>> mdadm: array /dev/md0 started. >>>> + mdadm --wait /dev/md0 >>>> + cat /proc/mdstat >>>> Personalities : [raid6] [raid5] [raid4] [raid1] >>>> md0 : active raid1 loop2[2] loop1[1] loop0[0] >>>> 19968 blocks super 1.2 [3/3] [UUU] >>>> >>>> unused devices: <none> >>>> + mdadm -S /dev/md0 >>>> mdadm: stopped /dev/md0 >>>> + mdadm -B /dev/md0 -l raid1 -n2 /dev/loop0 /dev/loop1 >>>> mdadm: array /dev/md0 built and started. >>>> + sleep 2 >>>> + cat /proc/mdstat >>>> Personalities : [raid6] [raid5] [raid4] [raid1] >>>> md127 : inactive md0[0](S) >>>> 19968 blocks super 1.2 >>>> >>>> md0 : active raid1 loop1[1] loop0[0] >>>> 20000 blocks super non-persistent [2/2] [UU] >>>> >>>> unused devices: <none> >>>> [root@dhcp-12-171 bug]# uname -r >>>> 4.2.0 >>>> [root@dhcp-12-171 bug]# mdadm -D /dev/md0 >>>> /dev/md0: >>>> Version : >>>> Creation Time : Mon Sep 7 20:21:20 2015 >>>> Raid Level : raid1 >>>> Array Size : 20000 (19.53 MiB 20.48 MB) >>>> Used Dev Size : 20000 (19.53 MiB 20.48 MB) >>>> Raid Devices : 2 >>>> Total Devices : 2 >>>> >>>> State : clean >>>> Active Devices : 2 >>>> Working Devices : 2 >>>> Failed Devices : 0 >>>> Spare Devices : 0 >>>> >>>> Number Major Minor RaidDevice State >>>> 0 7 0 0 active sync /dev/loop0 >>>> 1 7 1 1 active sync /dev/loop1 >>>> [root@dhcp-12-171 bug]# mdadm -D /dev/md127 >>>> /dev/md127: >>>> Version : 1.2 >>>> Raid Level : raid0 >>>> Total Devices : 1 >>>> Persistence : Superblock is persistent >>>> >>>> State : inactive >>>> >>>> Name : dhcp-12-171.nay.redhat.com:0 (local to host dhcp-12-171.nay.redhat.com) >>>> UUID : 40ace956:a9dd0793:f4984d2b:8431b92b >>>> Events : 17 >>>> >>>> Number Major Minor RaidDevice >>>> >>>> - 9 0 - /dev/md0 >>>> >>>> Best Regards, >>>> Yi Zhang ^ permalink raw reply [flat|nested] 5+ messages in thread
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2015-09-07 12:27 ` md127 auto created when use "-B" to build a legacy array without superblocks Yi Zhang
2015-10-02 7:55 ` Neil Brown
2016-01-26 8:24 ` yizhan
2016-01-26 22:03 ` NeilBrown
2016-01-27 9:18 ` yizhan
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