Phillip, et al --
...and then Phillip Susi said...
%
% David T-G <davidtg+robot@xxxxxxxxxxxxxxx> writes:
%
% > davidtg@gezebel:/mnt/data/tmp/4Traid> parallel 'size=$(sudo blockdev
% > --getsize {}); loop=$(sudo losetup -f --show -- overlay-{/}) ; echo
% > $loop' ::: $DEVICES
...
% > davidtg@gezebel:/mnt/data/tmp/4Traid> sudo losetup -a
...
% > ### why are these out of order?!? *sigh*
%
% Because you ran the command to create them with parallel. Don't do that.
Ah. Well, yeah; I'd like to not, not least because I don't have parallel
on all machines and I don't know its grammar enough to know what it's
really doing. But I also know that sometimes I should just shut up and
follow the documentation :-)
And I would figure that parallel would process them in order since they
should all take the same amount of time to run! But that's MUTEX play
for ya.
%
% > OK, yeah, we could predict that. But it gets even more fun:
...
% > What?!? Where is my superblock? This is a bit-for-bit copy of the
% > partition itself.
% >
% > Time to fall back for more help from the RAID gods *sigh* Any further
% > recommendations?
%
% Run mdadm -E /dev/loop{0,1,2}
Well, that appears to agree:
diskfarm:/mnt/10Traid50md/tmp # mdadm -E /dev/loop{0,1,2}
mdadm: No md superblock detected on /dev/loop0.
mdadm: No md superblock detected on /dev/loop1.
mdadm: No md superblock detected on /dev/loop2.
diskfarm:/mnt/10Traid50md/tmp # losetup -a
/dev/loop1: [66326]:1059 (/mnt/10Traid50md/tmp/overlay-sdb1)
/dev/loop2: [66326]:1060 (/mnt/10Traid50md/tmp/overlay-sdc1)
/dev/loop0: [66326]:1058 (/mnt/10Traid50md/tmp/overlay-sda1)
But I'm confused, all right:
diskfarm:/mnt/10Traid50md/tmp # mdadm -E 4Tsda1.EYNA.dd-bs\=256M-conv\=sparse\,noerror
4Tsda1.EYNA.dd-bs=256M-conv=sparse,noerror:
Magic : a92b4efc
Version : 1.2
Feature Map : 0x0
Array UUID : ca7008ef:90693dae:6c231ad7:08b3f92d
Name : diskfarm:0 (local to host diskfarm)
Creation Time : Mon Feb 6 05:56:35 2017
Raid Level : raid5
Raid Devices : 4
Avail Dev Size : 7813510799 sectors (3.64 TiB 4.00 TB)
Array Size : 11720265216 KiB (10.92 TiB 12.00 TB)
Used Dev Size : 7813510144 sectors (3.64 TiB 4.00 TB)
Data Offset : 262144 sectors
Super Offset : 8 sectors
Unused Space : before=262064 sectors, after=574835712 sectors
State : clean
Device UUID : f05a143b:50c9b024:36714b9a:44b6a159
Update Time : Sun Nov 7 01:00:00 2021
Checksum : 4adb8b59 - correct
Events : 128116
Layout : left-symmetric
Chunk Size : 512K
Device Role : Active device 3
Array State : A.AA ('A' == active, '.' == missing, 'R' == replacing)
OH!!! Wait. The loopback device points to the overlay file, which is
sparse. No wonder it has no superblock. When I was here on this host
after having lots of device mapper issues, I tried to assemble the files
and got nowhere.
Can I create loopback devices pointing to the image files, which will
give me raw handles, and then assemble that?
Or am I stuck with struggling with the mapper on my workstation with the
actual disks in it and wondering why sda1
davidtg@gezebel:/mnt/data/tmp/4Traid> sudo losetup -a
/dev/loop1: [66307]:624372298 (/mnt/data/tmp/4Traid/overlay-sdc1)
/dev/loop2: [66307]:624372297 (/mnt/data/tmp/4Traid/overlay-sdb1)
/dev/loop0: [66307]:624372296 (/mnt/data/tmp/4Traid/overlay-sda1)
davidtg@gezebel:/mnt/data/tmp/4Traid> echo 0 `sudo blockdev --getsize
/dev/sda1` snapshot /dev/sda1 /dev/loop0 P 8 | sudo dmsetup create sda1
device-mapper: reload ioctl on sda1 failed: Device or resource busy
Command failed.
is busy?
Thanks again & HANN
:-D
--
David T-G
See http://justpickone.org/davidtg/email/
See http://justpickone.org/davidtg/tofu.txt
