# mdadm --create --verbose /dev/md4 --name=4 --level=mirror --raid-devices=2 --metadata=0.90 /dev/sda4 /dev/sdb4 Expecting: /dev/md4 or /dev/md/4 Actual result: /dev/md/4_0 and /dev/md125 What does the trailing "_0" mean in /dev/md/4_0? # mkfs.ext4 -j /dev/md/4_0 # mount /dev/md/4_0 /mnt/gentoo where /dev/md/4_0 is a symlink to md125 # mount Expecting: /dev/md/4_0 on /mnt/gentoo type ext4 (rw) Actual result: /dev/md125 on /mnt/gentoo type ext4 (rw) # uname -a Linux livecd 3.10.25-gentoo #1 SMP Tue Feb 11 06:00:53 UTC 2014 i686 Intel(R) Pentium(R) 4 CPU 1.80GHz GenuineIntel GNU/Linux
can't reproduce w/mdadm-3.3.2 # mdadm --create --verbose /dev/md4 --name=4 --level=mirror \ --raid-devices=2 --metadata=0.90 /dev/loop[67] mdadm: size set to 10176K mdadm: array /dev/md4 started. # ls /dev/md4* -l brw-rw---- 1 root disk 9, 4 Apr 4 17:52 /dev/md4 please post emerge info as an attachment, as well as the versions of mdadm/udev you're using, and your kernel config.
It was a Gentoo live CD as shown in the first post but I didn't think of grabbing an emerge info. Anyway, this report is old now and I guess it can be closed if it's OK with you. I'll re-post if I ever encounter the issue again.
(In reply to Vieri from comment #2) sounds good, thanks