New answers tagged mdadm
For some reason, you seem to have used the whole disk for one of the drives, and a single partition on each of the other two. Try assembling using the partitions. mdadm --assemble /dev/sdb /dev/sd[cd]1
--create will create an array, not assemble it - use --assemble for that. If that doesn't help, look at /proc/mdstat before going any further. Your examine output indicates all array members are present. EDIT: Your drives sdc and sdd apparently have a protective MBR (indicated by partition type EE), i.e. they carry a GPT partition table. Maybe you are ...
I discovered my answer here. - "With mdadm, a 2 drive RAID 5 is binary identical to a RAID1, not RAID 0"
from my understanding the stipe_cache_size is the number of entries in the stripe cache. it affect only raid5. here are 2 documentation references: - https://github.com/torvalds/linux/blob/master/Documentation/md.txt#L603 - https://raid.wiki.kernel.org/index.php/Performance#Some_problem_solving_for_benchmarking
This is not specific to EBS, but there is good news in the release announcement for mdadm 3.3: This is a major new release so don't be too surprised if there are a few issues... Some highlights are: ... RAID10 arrays can be reshaped to change the number of devices, change the chunk size, or change the layout between 'near' and ...
You should use "--re-add" to add the removed disk back, like this: # mdadm /dev/md0 --re-add /dev/sdf2 I just tried it, and it worked, without a rebuild - if the disk has been removed beforehand using "--remove", like you did. Note that this is important - the disk has to have been removed using "--remove". If you just pull a disk out hard, plug it back ...
I finally got it working with debconf-set-selections This is what I did before installing mdadm - echo "mdadm mdadm/mail_to string root" | debconf-set-selections - echo "mdadm mdadm/initrdstart string all" | debconf-set-selections - echo "mdadm mdadm/autostart boolean true" | debconf-set-selections - echo "mdadm mdadm/autocheck boolean true" | ...
A better strategy would be to use ddrescue to copy bad drive to good. This tool tries hard to read entire drive, doing re-reads and "trimming" unreadable blocks. It also produces log, which is used for saving progress, but ultimately will contain the list of bad blocks. You can then parse this list and write to every bad block to see if the drive will ...
md127 is what results when you "split brain" a RAID1 array. The kernel starts numbering them in reverse to avoid conflicts with existing configured devices. It is counting that spare disk as a member of an unknown RAID1 array. I don't know why it assigned the other one as md2. That's a mystery.
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