On Mon, Apr 18, 2011 at 2:38 AM, NeilBrown <neilb@xxxxxxx> wrote: > On Fri, 15 Apr 2011 16:15:50 +0200 Seblu <seblu@xxxxxxxxx> wrote: > >> On Tue, Apr 5, 2011 at 8:20 AM, NeilBrown <neilb@xxxxxxx> wrote: >> > On Sun, 3 Apr 2011 18:03:50 +0200 Seblu <seblu@xxxxxxxxx> wrote: >> > >> >> Hello, >> >> >> >> In the following commit, udev rules load isw_raid (fakeraid). From my >> >> test, this doesnt work. I have to call dmraid to have something >> >> working. >> >> http://neil.brown.name/git?p=mdadm;a=commit;h=475a01b8bce8575dd1b2ab6495e65e854702ac0e >> >> >> >> isw_raid is only fakeraid devices? mdadm is able to mount fakeraid partition? >> >> >> > >> > I'm sorry but I cannot parse those questions successfully so I'm not sure >> > what you are asking. >> >> Hello Neil, >> >> in my previous mail, i used word fakeraid about raid created with >> dmraid and i used softraid about raid created with mdadm. it was not >> clear. >> >> So my question was about compatibily. Raids created by dmraid can be >> assembled with mdadm and vice versa? >> >> > Both dmraid and mdadm can manage some 'fakeraid' arrays. dmraid supports a >> > wider variety. mdadm supports raid1 and raid5 more completely than dmraid >> > does. >> mdadm -> create soft raid for linux (now there is new format: ddf and imsm) ? >> dmraid -> create soft raid from industry raid card format ? > > No, it isn't that simple. > > dmraid uses the 'dm' kernel module. mdadm uses the 'md' kernel module. > > As such dmraid doesn't support RAID5 (yet) and doesn't support RAID1 very > well. > mdadm supports both of these well, but doesn't support the same range of > "industry raid card formats". > > There is a growing amount of overlap. > >> >> > Both should support isw to some degree. >> > Intel are currently working with mdadm to make it provide full support for >> > "IMSM" (Intel Matrix Storage Manager). I don't know the exact relationship >> > between 'isw' and 'IMSM' - maybe they are different names for the same thing. >> ok >> >> > If mdadm doesn't work for your isw arrays, and you want it to, then I suggest >> > you report details about what is, or is not, happening. >> My purpose is to improve archlinux startup detection of fakeraids >> (mdadm + dmraid). >> >> With mdadm everything works correctly without call to "mdadm -As" >> With dmraid, no raid is created by udev rules, so we need to run >> "dmraid -i -ay" at startup. >> >> To test this kind of raid, i created a dmraid array in a vm. This >> created me a /dev/mapper/isw_bfbjdbadhb_testF device. >> call blkid on a disk member of this raid tell me this: >> /dev/sde: TYPE="isw_raid_member" >> and on "mdadm" created raid: >> /dev/sdd: UUID="a974b525-993a-1481-f860-6471f3f120e1" >> UUID_SUB="eb22aee2-b2ee-e56d-1008-44d52c63564d" LABEL="archipel:0" >> TYPE="linux_raid_member" >> >> This misled me because mdadm udev rules uses the output of blkid to >> mount raids which have type "isw_raid_member". >> What disturbs me is that mdadm cannot mount raid created by dmraid >> with type isw_raid_member. >> >> About outputs: >> mdadm -I --verbose /dev/sde >> mdadm: no RAID superblock on /dev/sde. > > As has been mentioned elsewhere, mdadm only recognised IMSM arrays on > machines with IMSM hardware. I'm not entirely happy about this and may well > change it. > > >> >> # mdadm --examine /dev/sde >> /dev/sde: >> Magic : Intel Raid ISM Cfg Sig. >> Version : 1.1.00 >> Orig Family : 5a8ed623 >> Family : 5a8ed623 >> Generation : 00000000 >> UUID : ae2e9cd8:7fa43248:47c694a1:24990cbc >> Checksum : c23b6c88 correct >> MPB Sectors : 1 >> Disks : 2 >> RAID Devices : 1 >> >> Disk00 Serial : 66faec8-9f5b237d >> State : active >> Id : 00040000 >> Usable Size : 1019486 (497.88 MiB 521.98 MB) >> >> [testF]: >> UUID : 6640a4cc:5faa1ce3:c1bff2b3:1093ca7d >> RAID Level : 1 >> Members : 2 >> Slots : [UU] >> Failed disk : none >> This Slot : 0 >> Array Size : 1014446 (495.42 MiB 519.40 MB) >> Per Dev Size : 1014792 (495.59 MiB 519.57 MB) >> Sector Offset : 0 >> Num Stripes : 3963 >> Chunk Size : 64 KiB >> Reserved : 0 >> Migrate State : idle >> Map State : normal >> Dirty State : clean >> >> Disk01 Serial : 0b540c6-4e527908 >> State : active >> Id : 00050000 >> Usable Size : 1019486 (497.88 MiB 521.98 MB) >> >> >> Do not you think that dmraid should also ship an udev rules file to >> mount the raid which can handle? > > I have no opinion about what dmraid should do. I have enough trouble working > out what mdadm should do :-) > Thanks Neil, it's more clear. Regards, -- Sébastien Luttringer www.seblu.net -- To unsubscribe from this list: send the line "unsubscribe linux-raid" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
