So I posted about my RAID solution plenty of times, but I have some additional information.
So here're my current harddrives:
# lsscsi [0:0:0:0] disk ATA Samsung SSD 860 1B6Q /dev/sda [4:0:0:0] disk ATA WDC WD4003FZEX-0 1A01 /dev/sdb [5:0:0:0] disk ATA WDC WD5000AAKS-0 3B01 /dev/sdc [5:0:1:0] disk ATA ST2000DM001-1CH1 CC29 /dev/sdd [10:0:0:0] disk WD Ext HDD 1021 2021 /dev/sde [11:0:0:0] disk WD Ext HDD 1021 2021 /dev/sdf
Three harddrives of which I use for my RAID 1. One internal SATA drive and two external USB drives.
/dev/sdd - harddrive 2 TB ./dev/sdd1 2048 3907024895 3907022848 1.8T fd Linux raid autodetect /dev/sde - external WD harddrive 2 TB /dev/sde1 2048 3907024895 3907022848 1.8T fd Linux raid autodetect /dev/sdf - external WD harddrive 2 TB /dev/sdf1 2048 3907024895 3907022848 1.8T fd Linux raid autodetect
And then I had a problem.
# mdadm --detail /dev/md127
/dev/md127:
Version : 1.2
Creation Time : Wed Mar 6 22:16:05 2013
Raid Level : raid1
Array Size : 1953380160 (1862.89 GiB 2000.26 GB)
Used Dev Size : 1953380160 (1862.89 GiB 2000.26 GB)
Raid Devices : 3
Total Devices : 2
Persistence : Superblock is persistent
Update Time : Sat Nov 27 20:57:13 2021
State : clean, degraded
Active Devices : 2
Working Devices : 2
Failed Devices : 0
Spare Devices : 0
Consistency Policy : resync
Name : micemouse:0
UUID : ed4531c4:59c132b2:a6bfc3d1:6da3b928
Events : 6205
Number Major Minor RaidDevice State
2 8 65 0 active sync /dev/sde1
- 0 0 1 removed
3 8 49 2 active sync /dev/sdd1
For some reason, we're missing /dev/sdf with partition /dev/sdf1.
I am fairly concerned here.
So I reattached the device, and then had to rebuild, etc, etc and it took a few days.
A better solution would have been to prevent the automounting of raid arrays, until I've attached said external drives.
They are not attached by default.
Turning off auto raid detection
The reason I wanted to turn off automatic raid detection, is because I have two disks that can be attached via USB that are part of the RAID array.
When they are not attached, and the raid is autodetected, this time it started up with one device removed.
And it takes a dickens of a time to reattach the devices to the raid.
Sometimes the configuration is simply not there (autodetects the superblock on drives, and works it out from there).
If it is there, it should be either in:
- /etc/mdadm/mdadm.conf
- for some Linux, for example Ubuntu.
- /etc/mdadm.conf
- for some Linux, for example Fedora.
Simply adding the following should be enough:
A better way would probably be to have stopped the raid, and re-assemble it again.
Will try this next time if it happens.
Stopping an array
Starting an Array
For simple setups:
For specific setups:
For machine/harddrive independent setup (he gathers the appropriate components itself):
And then you can do:
References
- DigitalOcean - How To Manage RAID Arrays with mdadm on Ubuntu 16.04
- https://www.digitalocean.com/community/tutorials/how-to-manage-raid-arrays-with-mdadm-on-ubuntu-16-04
- Re: turn off auto assembly
- https://www.spinics.net/lists/raid/msg30997.html
