On Wed, 14 Jul 2010 12:53:45 +0200
Tomasz Chmielewski <mangoo@xxxxxxxx> wrote:
> I'm trying to create RAID-1 with external bitmap with this command:
>
> mdadm --create /dev/md11 --level=1 --bitmap=/mnt/src/bitmap --raid-devices 2 /dev/storage/origin missing
>
>
> /dev/storage/origin is 1.2 TB; is placed on "stacked" block devices like this:
>
> RAID-5 -> dm-crypt -> LVM-2 -> /dev/storage/origin
>
>
> /mnt/src/bitmap is technically the same stacked device, except the last LVM volume:
>
> RAID-5 -> dm-crypt -> LVM-2 -> /dev/storage/src -> /mnt/src/bitmap
>
> (although I tried to keep bitmap outside of this RAID-5 device, and it was still hanging).
>
>
> When started with "strace", mdadm hangs with 100% CPU usage after opening /mnt/src/bitmap:
>
> (...)
> rename("/var/run/map.new", "/var/run/map") = 0
> flock(3, LOCK_UN) = 0
> close(3) = 0
> munmap(0x6ff40000, 4096) = 0
> unlink("/var/run/map.lock") = 0
> ioctl(4, 0x800c0910, 0x77f5f89c) = 0
> fstat64(4, {st_mode=S_IFBLK|0600, st_rdev=makedev(9, 1), ...}) = 0
> fstat64(4, {st_mode=S_IFBLK|0600, st_rdev=makedev(9, 1), ...}) = 0
> ioctl(4, 0x800c0910, 0x77f5f7cc) = 0
> ioctl(4, 0x40480923, 0x77f5f854) = 0
> access("/mnt/src/bitmap", F_OK) = -1 ENOENT (No such file or directory)
> open("/mnt/src/bitmap", O_WRONLY|O_CREAT|O_TRUNC|O_LARGEFILE, 0666) = 3
>
>
Hmm... that's rather embarrassing.
This patch should fit it. Or you can explicitly set a bitmap chunk size -
aim for several megabyte.
Thanks for the report,
NeilBrown
diff --git a/bitmap.c b/bitmap.c
index beef2dc..44a8677 100644
--- a/bitmap.c
+++ b/bitmap.c
@@ -373,7 +373,7 @@ int CreateBitmap(char *filename, int force, char uuid[16],
*/
chunksize = DEFAULT_BITMAP_CHUNK;
/* <<20 for 2^20 chunks, >>9 to convert bytes to sectors */
- while (array_size > (chunksize << (20-9)))
+ while (array_size > ((unsigned long long)chunksize << (20-9)))
chunksize <<= 1;
}
> I see no disk activity when this happens.
>
>
> # mdadm -V
> mdadm - v3.1.2 - 10th March 2010
>
> Kernel is 2.6.34.1 (tried also 2.6.28.7), 32 bit x86 system.
>
> Or, I didn't wait long enough? So far, it takes about an hour to create this array...
>
> Creating smaller arrays (i.e. 8 GB) in a similar configuration works fine.
>
>
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