Hi,
I've tried the latest version of mdadm
and the problem still exists.
I believed it was because in add_internal_super1, variable "room"
overflowed that made it become a negative value,
and if room less than 3 * 2 and also __le32_to_cpu(sb->max_dev) <= 384
room would become 6, and max_bits became extremely small,
unfortunately, this is a 2T array, so the bitmap creation failed.
I still wondered, why would mdadm stored the value (if specified)
to rdev->sectors other than just make it to the largest.
In Grow_reshape (Grow.c)
/* Update the size of each member device in case
* they have been resized. This will never reduce
* below the current used-size. The "size" attribute
* understands '0' to mean 'max'.
*/
min_csize = 0;
for (mdi = sra->devs; mdi; mdi = mdi->next) {
sysfs_set_num(sra, mdi, "size",
s->size == MAX_SIZE ? 0 : s->size);
^^^^^^^^
Thanks,
‐‐‐‐‐‐‐ Original Message ‐‐‐‐‐‐‐
On 2020年5月26日Tuesday 18:14, antlists <antlists@xxxxxxxxxxxxxxx> wrote:
> On 26/05/2020 04:40, Jonas Fisher wrote:
>
> > Hi all,
> > I got a raid1 composed with 2 disks
> > /dev/sda -- 2T
> > /dev/sdb -- 4T
> > mdadm version is 3.3 and md metadata version is 1.0
>
> That's a well ancient mdadm, you need to upgrade ...
>
> > At first, I was only using 1T of the each disk,
> > then I grew the array recently with the command
> > mdadm --grow /dev/md1 --size=1951944704K
> > I also tried to add the internal bitmap after expansion finished
> > mdadm --grow /dev/md1 --bitmap=internal
> > But I got the following message
> > mdadm: failed to create internal bitmap - chunksize problem.
> > I found that Avail Dev Size in superblock examine of two disks
> > are the same, same as the value I set when I expanded the array (1951944704K).
>
> Makes sense, it's a mirror ...
>
> > Then I found that in mdadm bitmap chunksize calculation,
> > in function add_internal_bitmap1 (super1.c)
> > variable "room" and and "max_bits" seems to be overflowed under this situation
>
> Could well be fault of the old mdadm ...
>
> > I was wondering is this because mdadm set the size of the rdevs in the array
> > before doing expansion (in function Grow_reshape)
> > that caused the sb->data_size not equals to actual raw device size
> > and consequently led to bitmap chunksize calculation error
> > or it is simply a data type issue.
> > Thanks,
>
> Download and run a new mdadm. If the problem still persists, then I
> guess the mdadm guys will take a look.
>
> https://raid.wiki.kernel.org/index.php/Linux_Raid
>
> https://raid.wiki.kernel.org/index.php/A_guide_to_mdadm#Getting_mdadm
>
> It seems odd to be mirroring a 2TB and 4TB, but never mind. It's not
> (that much) a problem if you're using desktop drives for a mirror, but
> if you do get a new 4TB drive, read the advice on the website and make
> sure you get a proper raid drive.
>
> Cheers,
> Wol
