Hi, Am Mittwoch, 10. November 2021, 14:09:53 CET schrieb Markus Hochholdinger: > Am Samstag, 24. März 2012, 21:47:15 CET schrieb Markus Hochholdinger: > > it's been a long time, but today I tried again and had success! > > Am 28.06.2008 um 01:41 Uhr schrieb Neil Brown <neilb@xxxxxxx>: > > > On Friday June 27, Markus@xxxxxxxxxxxxxxxxx wrote: > > > > Am Freitag, 27. Juni 2008 08:51 schrieb NeilBrown: > > > > > From: Chris Webb <chris@xxxxxxxxxxxx> > > [..] > > > You don't want to "mdadm --grow" until everything has been resized. > > > First lvresize one disk, then write '0' to the .../size file. > > > Then do the same for the other disk. > > > Then "mdadm --grow /dev/mdX --size max". > > it works for me, if I do: > > echo 0 > /sys/block/md2/md/rd0/size > > mdadm --grow /dev/md2 --size=max > > # till here, nothing happens > > echo 0 > /sys/block/md2/md/rd1/size > > mdadm --grow /dev/md2 --size=max > > # rebuild of the added space begins > This has been working for me till at least kernel 4.19.x and I first > recognized it not working anymore with kernel 5.10.x . So inbetween > something changed regarding the resize and grow of md raid1 with superblock > version 1.0. The grow still works and a rebuild is done, but afterwards the > superblock isn't created/moved to the new end of the devices. The raid1 > works until you stop it, but you won't be able to re-assemble it > (re-creating works). While re-creating I recognized the grown filesystem > (after the raid1 was grown) was too large (fsck complained). > I already tracked it down to the version of the metadata/superblock. With > version 1.0 (superblock at the end) the above fails and it looks like the > superblock on the grown device is somehow there but with wrong informations > (mdadm --zero-superblock has removed something while mdadm -D .. tells me, > there's no superblock). > All works fine with superblock version 1.2 (superblock at the beginning). > Any ideas what could have changed so the grow feature for raid1 with > superblock version 1.0 isn't working anymore? > For now the workaround is to really remove a grown device from the raid1 and > do a full rebuild before re-adding the other grown device. > I'll test the different kernel versions to see, where/when this feature was > lost. It is working es (I) expected till at least kernel 5.4.158. It is not working with 5.10.x till 5.15.1. On my old systems (kernel <= 5.4.x) after resizing one component mdadm -E /dev/xvda2 is able to see the moved superblock only after echo 0 > /sys/block/md2/md/rd0/size On new systems (kernel >= 5.10.0) it doesn't matter if I issue echo 0 > /sys/block/md2/md/rd0/size mdadm -E keeps complaining about no superblock on the grown device. (The bitmap was removed before the echo 0 and I tried to remove the bitmap at all before resizing, still the same issue.) It's only possible to remove the changed device and add with a full rebuild. But this isn't possible, if both devices were resized before. mdadm complains about no metadata available, no matter what I do while the md raid1 is still running (where is the superblock updated on the disks then?). > > If I do only: > > echo 0 > /sys/block/md2/md/rd0/size > > echo 0 > /sys/block/md2/md/rd1/size > > mdadm --grow /dev/md2 --size=max > > > > nothing will change. > > As I understand, with "echo 0" md sees the new size and only with --grow > > the superblock will be moved. > > I'm doing this with 2.6.32-5-xen-686 within Debian (squeeze) 6.0. > > Many thanks to you and all the other linux-raid developers for this > > feature! I'm very happy about this :-) -- Mfg Markus Hochholdinger
