Useful for long web pages: Cmd + Up/Down (from here)
Rebuilding a software controlled RAID on Ubuntu
One of my RAID arrays on my server decided that one of the drives was bad and dropped it out of my array. I have two software defined RAID 1 mirrored arrays, /dev/md0 which contains my main drives, and then a smaller array, /dev/md1
This is what mdadm was showing for when one of the drives was dropped out:
kevin@linuxsvr:~$ sudo mdadm --detail /dev/md1 /dev/md1: Version : 0.90 Creation Time : Sat May 16 18:38:51 2009 Raid Level : raid1 Array Size : 1485888 (1451.31 MiB 1521.55 MB) Used Dev Size : 1485888 (1451.31 MiB 1521.55 MB) Raid Devices : 2 Total Devices : 1 Preferred Minor : 1 Persistence : Superblock is persistent Update Time : Tue Mar 5 14:10:24 2013 State : clean, degraded Active Devices : 1 Working Devices : 1 Failed Devices : 0 Spare Devices : 0 UUID : 44b55b61:84e84f5f:5c7760e0:2ac997c6 Events : 0.90560 Number Major Minor RaidDevice State 0 8 21 0 active sync /dev/sdb5 1 0 0 1 removed
I couldn’t find any messages in syslog for what was wrong with my drive, and the SMART status for both drives was still good. I did have to power off the server to move it without a clean shutdown, so this was probably self-inflicted…
On one of my arrays, adding back the missing drive caused it to add as a spare, it re-sync’d and then everything was back to normal. On the other, it wouldn’t add back:
kevin@linuxsvr:~$ sudo mdadm --add /dev/md1 /dev/sdc5 mdadm: /dev/sdc5 reports being an active member for /dev/md1, but a --re-add fails. mdadm: not performing --add as that would convert /dev/sdc5 in to a spare. mdadm: To make this a spare, use "mdadm --zero-superblock /dev/sdc5" first.
I found a few posts describing to fail the drive, remove and then add it back, but this still gave the same error:
sudo mdadm --manage /dev/md1 --fail /dev/sdc5 sudo mdadm --manage /dev/md1 --remove /dev/sdc5 sudo mdadm --manage /dev/md1 --add /dev/sdc5
I don’t know exactly what the recommendation in the error message did, but using the –zero-superblock option and then adding back the drive again did the job. It resync’d successfully and everything’s back to normal.
This post on StackExchange has some good info and suggestions. This one too.
webOS gets another chance with LG
After HP bought Palm and promised to ‘double down’ on webOS usage across HP products from printers to PCs, it really went no-where after it’s too expensive TouchPad failed to sell.
LG announced this morning that it is buying all webOS assets from HP, with plans to use the OS in it’s new TVs. Interesting move, and looks like webOS may have another chance yet.
Overlapping hobbies: computer technology and Ham radio – Ham Radio Now’s interview with TWiT
I probably have far too many hobbies 🙂 I’ve always been interested in radio communications, and I’ve decided recently I’m going to take the plunge and get my Technician ham radio license. I was just watching a past episode of Ham Radio Now where they went and toured Leo Laporte’s TWiT studios in Petaluma, and wow, holy cow, I had no idea how much was actually involved behind the scenes at the TWiT studios, my jaw was on the floor.
This is a fantastic behind the scenes look at what’s involved in producing the TWiT shows, well worth a watch (check out part 2) if you’re familiar with Leo’s shows or are just interested in what’s involved to produce an online video podcast based show:Â http://arvideonews.com/hrn/HRN_Episode_0032.html