mdadm interview questions
Top mdadm frequently asked interview questions
my raid 5 (md0) stopped working and after some poking around I found that
/dev/sdc:
Update Time : Fri Dec 20 05:03:06 2013
Events : 88
/dev/sdd:
Update Time : Sun Jun 5 02:00:03 2016
Events : 3299448
/dev/sde:
Update Time : Sun Jun 5 19:25:45 2016
Events : 3299455
Is it safe for my data to force assemble the raid? Should I replace sdc first?
Source: (StackOverflow)
I need to be able to call this:
watch -n1 cat /proc/mdstat
from bash.
For raid creating watching (after mdadm --create etc.), and then kill it then building process will end.
#!/bin/bash
#PID=$!
while
progress=$(cat /proc/mdstat |grep -oE 'recovery = ? [0-9]*')
do
watch -n1 cat /proc/mdstat
PID=$(pidof watch)
echo "$PID" >> /mnt/pid
if (("$progress" >= "100"))
then
break
kill -9 $PID
fi
done
echo "done"
But I can not figure out how to kill watch out from bash. I tried PID=$! and PID=$$, pidof watch at the cycle and out of him, but can't assign correct PID to my variable to make kill -9 $PID.
Source: (StackOverflow)
So I know how to expose a local disk to an ESXI guest via
vmkfstools -z /vmfs/devices/disks/t10.ATA___** /vmfs/volumes/datastore1/LocalDisks/
This works great! My thought then would be to create an MD0 inside of an Ubuntu Server and export that via NFS and SMB. The NFS would be for other internal ESXI linux guests and SMB for Windows only.
Does this sound like a bad idea? Any special export parameters I should use for NFS?
Currently to make NFS exporting to other local esxi guests work I use
(rw,async,insecure,no_subtree_check,nohide,no_root_squash)
And to mount I use
nosharecache,context="system_u:object_r:httpd_sys_rw_content_t:s0" 0 0"
I should note, the esxi host/datastore is on a seperate HD not part of md0 and that the data will be mostly static. No large DBs or anything, a lot of media. The most heavy IO would be ZoneMinder (motion detection suite that saves images and compares them constantly)
Source: (StackOverflow)
When I try to mount one of my hard drives, it can't locate the folder with the hard drive.
This is the output for the command df:
Filesystem 1K-blocks Used Available Use% Mounted on
rootfs 33000428 119124 32881304 1% /
none 33000428 119124 32881304 1% /
198.27.85.63:/home/pub/rescue.v7 886788312 250295096 591423904 30% /nfs
198.27.85.63:/home/pub/pro-power 886788312 250295096 591423904 30% /power
198.27.85.63:/home/pub/commonnfs 886788312 250295096 591423904 30% /common
tmpfs 10240 204 10036 2% /dev
tmpfs 6600088 72 6600016 1% /run
tmpfs 5120 0 5120 0% /run/lock
tmpfs 13200160 0 13200160 0% /run/shm
This comes when I run the command fdisk -l:
WARNING: GPT (GUID Partition Table) detected on '/dev/sdb'! The util fdisk doesn't support GPT. Use GNU Parted.
Disk /dev/sdb: 2000.4 GB, 2000398934016 bytes
255 heads, 63 sectors/track, 243201 cylinders, total 3907029168 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x00000000
Device Boot Start End Blocks Id System
/dev/sdb1 1 3907029167 1953514583+ ee GPT
WARNING: GPT (GUID Partition Table) detected on '/dev/sda'! The util fdisk doesn't support GPT. Use GNU Parted.
Disk /dev/sda: 2000.4 GB, 2000398934016 bytes
255 heads, 63 sectors/track, 243201 cylinders, total 3907029168 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x00000000
Device Boot Start End Blocks Id System
/dev/sda1 1 3907029167 1953514583+ ee GPT
Disk /dev/md3: 1978.9 GB, 1978886193152 bytes
2 heads, 4 sectors/track, 483126512 cylinders, total 3865012096 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x00000000
Disk /dev/md3 doesn't contain a valid partition table
Disk /dev/md2: 21.0 GB, 20970405888 bytes
2 heads, 4 sectors/track, 5119728 cylinders, total 40957824 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x00000000
Disk /dev/md2 doesn't contain a valid partition table
When I try to mount the /dev/sda1 hard drive with the command mount -o barrier=0 /dev/sda1 it gives me this message:
mount: can't find /dev/sda1 in /etc/fstab or /etc/mtab
How can i fix this, so i can backup all of my stuff?
This comes when I try to mount /dev/sdb3:
mount: unknown filesystem type 'linux_raid_member'
Then I tried to use the command mdadm --assemble --run /mnt /dev/sdb3 but then it just gives me this:
mdadm: /dev/sdb3 is busy - skipping
This is my output from using cat /proc/mdstat
md2 : active raid1 sda2[0] sdb2[1]
20478912 blocks [2/2] [UU]
md3 : active raid1 sda3[0] sdb3[1]
1932506048 blocks [2/2] [UU]
unused devices: <none>
I can mount md3, but no files appears in the folder /mnt
Source: (StackOverflow)
I create a RAID1 device with mdadm in an EC2 instance. The version of mdadm is v3.3.2.
/sbin/mdadm --create /dev/md1 --level=1 --raid-devices=2 /dev/xvdf /dev/xvdk
This is the output of mdstat:
cat /proc/mdstat
Personalities : [raid1]
md1 : healthy raid1 xvdk[1] xvdf[0]
41594888 blocks super 1.2 [2/2] [UU]
It's normal. We see that there are two member disks xvdk and xvdf for this RAID1 device.
However, I find the members of MD device become /dev/sd* in "mdadm -D" output:
mdadm -D /dev/md1
/dev/md1:
Version : 1.2
Creation Time : Fri Dec 11 06:29:50 2015
Raid Level : raid1
...
Number Major Minor RaidDevice State
0 202 82 0 active sync /dev/sdf
1 202 162 1 active sync /dev/sdk
Then I find these links have been created automatically:
ll /dev/sd*
lrwxrwxrwx. 1 root root 4 Dec 11 06:29 /dev/sdf -> xvdf
lrwxrwxrwx. 1 root root 4 Dec 11 06:29 /dev/sdk -> xvdk
I guess that this is done by mdadm. I never saw this problem before.
I think it's no need to change device name of MD members because it confuses people. How to avoid this problem? Thanks a lot!
Source: (StackOverflow)
I have a software RAID5 built with 5 disks. There were some problems with system which I was trying to resolve with mondorescue. I've used "nuke" type of recovering which lead me to destroying of my RAID5 array. Now mdadm -D /dev/md0 shows me 4 disks are "removed", one disk is still "active". No superblock found on the "removed" disks, so, mdadm could not assemble this array back. Is there any chance to recover superblocks on the "removed" disks?
No badblocks on all disks at all, they all are clean. Please help.
mdadm --examine output:
[root@WWW /]# mdadm --examine /dev/sd[bcdef]1
mdadm: No md superblock detected on /dev/sdb1.
mdadm: No md superblock detected on /dev/sdc1.
mdadm: No md superblock detected on /dev/sdd1.
mdadm: No md superblock detected on /dev/sde1.
/dev/sdf1:
Magic : a92b4efc
Version : 1.2
Feature Map : 0x0
Array UUID : 50c0e8b8:0d80f11d:be9b2b55:1718bb55
Name : WWW:0 (local to host WWW)
Creation Time : Wed Jan 29 23:08:39 2014
Raid Level : raid5
Raid Devices : 5
Avail Dev Size : 5860268032 (2794.39 GiB 3000.46 GB)
Array Size : 11720534016 (11177.57 GiB 12001.83 GB)
Used Dev Size : 5860267008 (2794.39 GiB 3000.46 GB)
Data Offset : 258048 sectors
Super Offset : 8 sectors
Unused Space : before=257960 sectors, after=5120 sectors
State : clean
Device UUID : 9ed14cc6:2ca75f84:5b934993:63ca71fc
Update Time : Sun Nov 8 05:53:40 2015
Bad Block Log : 512 entries available at offset 72 sectors
Checksum : 1844f433 - correct
Events : 14622
Layout : left-symmetric
Chunk Size : 512K
Device Role : Active device 4
Array State : AAAAA ('A' == active, '.' == missing, 'R' == replacing)
Source: (StackOverflow)
One disk (sdc) of my RAID5 array (sda..sdf, 6 disks) down yesterday moning. I haven't backup any files or arrry information before. I replace it with a new one (still named sdc in my system, we call it NEW_sdc here), run:
mdadm --manage /dev/md1 --add /dev/NEW_sdc
I've done this many times. But last night, after rebuild (I guess, based on "Update time" listed), another disk (sda) down also. I've no idea how to recover this.
This morning, I found this and reboot system from LiveUSB and get following information.
I guess array can run on sdb, NEW_sdc, sdd, sde, sdf on degraded mode, then I can replace sda, or do some backup. But I don't know how.
Before reboot, I got details about array:
/dev/md1:
Version : 1.2
Creation Time : Mon Jan 5 11:39:44 2015
Raid Level : raid5
Array Size : 9766914560 (9314.46 GiB 10001.32 GB)
Used Dev Size : 1953382912 (1862.89 GiB 2000.26 GB)
Raid Devices : 6
Total Devices : 6
Persistence : Superblock is persistent
Update Time : Tue Sep 22 08:43:45 2015
State : clean, FAILED
Active Devices : 4
Working Devices : 5
Failed Devices : 1
Spare Devices : 1
Layout : left-symmetric
Chunk Size : 512K
Name : txds:1
UUID : 3dd22fc6:4226630e:efc3c5dc:909102ef
Events : 895156
Number Major Minor RaidDevice State
0 8 48 0 active sync /dev/sdd
8 8 64 1 active sync /dev/sde
2 8 80 2 active sync /dev/sdf
6 0 0 6 removed
8 0 0 8 removed
6 8 16 5 active sync /dev/sdb
4 8 0 - faulty /dev/sda
7 8 32 - spare /dev/sdc
Live system recognized raid array as RAID0!
/dev/md127:
Version: 1.2
Raid Level: raid0
Total Devices: 6
Persistence: Superblock is persistent
State: inactive
Name: txds:1
UUID: 3dd22fc6:4226630e:efc3c5dc:909102ef
Events: 890960
Number Major Minor RaidDevice
- 8 0 - /dev/sda
- 8 16 - /dev/sdb
- 8 32 - /dev/sdc
- 8 48 - /dev/sdd
- 8 64 - /dev/sde
- 8 80 - /dev/sdf
I've run "mdadm --stop /dev/md127". Then, examine on every disk:
examine on /dev/sda:
Magic: a92b4efc
Version: 1.2
Feature Map: 0x0
Array UUID: 3dd22fc6:4226630e:efc3c5dc:909102ef
Name: txds:1
Creation Time: Mon Jan 5 11:39:44 2015
Raid Level: raid5
Raid Devices: 6
Avail Dev Size: 3906767024 (1862.89 GiB 2000.26 GB)
Array Size: 9766914560 (9314.46 GiB 10001.32 GB)
Used Dev Size: 3906765824 (1862.89 GiB 2000.26 GB)
Data Offset: 262144 sectors
Super Offset: 8 sectors
Unused Space: before=262064 sectors, after=1200 sectors
State: clean
Device UUID: 6bae772e:30a94056:50a346d6:74e17539
Update Time: Mon Sep 21 21:51:17 2015
Checksum: cd94df52 - correct
Events: 890960
Layout: left-symmetric
Chunk Size: 512K
Device Role: Active device 4
Array State: AAAAAA ('A'==active, '.'==missing, 'R'==replacing)
examine on /dev/sdb:
Magic: a92b4efc
Version: 1.2
Feature Map: 0x0
Array UUID: 3dd22fc6:4226630e:efc3c5dc:909102ef
Name: txds:1
Creation Time: Mon Jan 5 11:39:44 2015
Raid Level: raid5
Raid Devices: 6
Avail Dev Size: 3906767024 (1862.89 GiB 2000.26 GB)
Array Size: 9766914560 (9314.46 GiB 10001.32 GB)
Used Dev Size: 3906765824 (1862.89 GiB 2000.26 GB)
Data Offset: 262144 sectors
Super Offset: 8 sectors
Unused Space: before=262064 sectors, after=1200 sectors
State: clean
Device UUID: 82028087:4d6bf8b6:b203ac87:8972ea0b
Update Time: Tue Sep 22 08:53:14 2015
Checksum: b2c9288 - correct
Events: 895160
Layout: left-symmetric
Chunk Size: 512K
Device Role: Active device 5
Array State: AAA..A ('A'==active, '.'==missing, 'R'==replacing)
examine on /dev/sdc:
Magic: a92b4efc
Version: 1.2
Feature Map: 0x0
Array UUID: 3dd22fc6:4226630e:efc3c5dc:909102ef
Name: txds:1
Creation Time: Mon Jan 5 11:39:44 2015
Raid Level: raid5
Raid Devices: 6
Avail Dev Size: 3906767024 (1862.89 GiB 2000.26 GB)
Array Size: 9766914560 (9314.46 GiB 10001.32 GB)
Used Dev Size: 3906765824 (1862.89 GiB 2000.26 GB)
Data Offset: 262144 sectors
Super Offset: 8 sectors
Unused Space: before=262056 sectors, after=1200 sectors
State: clean
Device UUID: 4a2aad92:b5c46b6f:88024745:8c979bc6
Update Time: Mon Sep 21 10:58:19 2015
Checksum: 47722b054 - correct
Events: 873820
Layout: left-symmetric
Chunk Size: 512K
Device Role: Active device 3
Array State: AAAAAA ('A'==active, '.'==missing, 'R'==replacing)
examine on /dev/NEW_sdc:
Magic: a92b4efc
Version: 1.2
Feature Map: 0x8
Array UUID: 3dd22fc6:4226630e:efc3c5dc:909102ef
Name: txds:1
Creation Time: Mon Jan 5 11:39:44 2015
Raid Level: raid5
Raid Devices: 6
Avail Dev Size: 3906767024 (1862.89 GiB 2000.26 GB)
Array Size: 9766914560 (9314.46 GiB 10001.32 GB)
Used Dev Size: 3906765824 (1862.89 GiB 2000.26 GB)
Data Offset: 262144 sectors
Super Offset: 8 sectors
Unused Space: before=262056 sectors, after=1200 sectors
State: clean
Device UUID: 5b971390:eb99b77b:fc46a10a:d45e433a
Update Time: Tue Sep 22 08:53:14 2015
Bad Block Log: 512 entries available at offset 72 sectors - bad blocks persent.
Checksum: 89d585e4 - correct
Events: 895160
Layout: left-symmetric
Chunk Size: 512K
Device Role: spare
Array State: AAA..A ('A'==active, '.'==missing, 'R'==replacing)
examine on /dev/sdd:
Magic: a92b4efc
Version: 1.2
Feature Map: 0x0
Array UUID: 3dd22fc6:4226630e:efc3c5dc:909102ef
Name: txds:1
Creation Time: Mon Jan 5 11:39:44 2015
Raid Level: raid5
Raid Devices: 6
Avail Dev Size: 3906767024 (1862.89 GiB 2000.26 GB)
Array Size: 9766914560 (9314.46 GiB 10001.32 GB)
Used Dev Size: 3906765824 (1862.89 GiB 2000.26 GB)
Data Offset: 262144 sectors
Super Offset: 8 sectors
Unused Space: before=262064 sectors, after=1200 sectors
State: clean
Device UUID: c0f4e974:8c16a6d2:0d88252d:94bbb9c5
Update Time: Tue Sep 22 08:53:14 2015
Checksum: 738cfd65 - correct
Events: 895160
Layout: left-symmetric
Chunk Size: 512K
Device Role: Active device 0
Array State: AAA..A ('A'==active, '.'==missing, 'R'==replacing)
examine on /dev/sde:
Magic: a92b4efc
Version: 1.2
Feature Map: 0x0
Array UUID: 3dd22fc6:4226630e:efc3c5dc:909102ef
Name: txds:1
Creation Time: Mon Jan 5 11:39:44 2015
Raid Level: raid5
Raid Devices: 6
Avail Dev Size: 3906767024 (1862.89 GiB 2000.26 GB)
Array Size: 9766914560 (9314.46 GiB 10001.32 GB)
Used Dev Size: 3906765824 (1862.89 GiB 2000.26 GB)
Data Offset: 262144 sectors
Super Offset: 8 sectors
Unused Space: before=262056 sectors, after=1200 sectors
State: clean
Device UUID: 8eef85af:81f164ea:f3c95a2c:cddb6340
Update Time: Tue Sep 22 08:53:14 2015
Bad Block Log: 512 entries available at offset 72 sectors
Checksum: 3fcf3597 - correct
Events: 895160
Layout: left-symmetric
Chunk Size: 512K
Device Role: Active device 1
Array State: AAA..A ('A'==active, '.'==missing, 'R'==replacing)
examine on /dev/sdf:
Magic: a92b4efc
Version: 1.2
Feature Map: 0x0
Array UUID: 3dd22fc6:4226630e:efc3c5dc:909102ef
Name: txds:1
Creation Time: Mon Jan 5 11:39:44 2015
Raid Level: raid5
Raid Devices: 6
Avail Dev Size: 3906767024 (1862.89 GiB 2000.26 GB)
Array Size: 9766914560 (9314.46 GiB 10001.32 GB)
Used Dev Size: 3906765824 (1862.89 GiB 2000.26 GB)
Data Offset: 262144 sectors
Super Offset: 8 sectors
Unused Space: before=262064 sectors, after=1200 sectors
State: clean
Device UUID: 4e7469d8:a9d5e8f4:a916bee4:739ccdb3
Update Time: Tue Sep 22 08:53:14 2015
Checksum: a9fbab84 - correct
Events: 895160
Layout: left-symmetric
Chunk Size: 512K
Device Role: Active device 2
Array State: AAA..A ('A'==active, '.'==missing, 'R'==replacing)
Source: (StackOverflow)
I have a Intel Rapid Storage Raid 5 with 4x 6TB disks (all space used as raid on ubuntu 14.04 with mdadm ),
I would like to add a write intended bitmap, such that recovery is faster.
I tried:
sudo mdadm --grow /dev/md126 --bitmap=internal
which outputs
mdadm: Cannot add bitmaps to sub-arrays yet
sudo mdadm --detail --scan
ARRAY /dev/md/imsm0 metadata=imsm UUID=e409a30d:353a9b11:1f9a221a:7ed7cd21
ARRAY /dev/md/vol0 container=/dev/md/imsm0 member=0 UUID=9adaf3f8:d899c72b:fdf41fd1:07ee0399
How can I achieve this and where is the problem?
Is the only option an external bitmap file?
Thanks for the help!
Source: (StackOverflow)
I'm trying to control mdadm from a Python script, and have a call similar to this:
subprocess.Popen('mdadm --create /dev/md1 --raid-devices=4 /dev/md-0 /dev/md-1 /dev/md-2 /dev/md-3'.split())
mdadm then complains with mdadm: You have listed more devices (5) than are in the array(4)!
When I use shell=True (or os.system), it works just fine. For example:
subprocess.Popen('mdadm --create /dev/md1 --raid-devices=4 /dev/md-0 /dev/md-1 /dev/md-2 /dev/md-3', shell=True)
Why does the call fail without shell=True?
EDIT: Here is the full string that I'm splitting up and passing to subprocess.Popen:
mdadm --create /dev/md10 --name /dev/md/demo --chunk=128K --level=raid6 --size=104857600 $MDADM_r6_OPT --spare-device=0 --raid-devices=8 /dev/mapper/mpathbp2 /dev/mapper/mpathbp3 /dev/mapper/mpathbp4 /dev/mapper/mpathbp5 /dev/mapper/mpathcp2 /dev/mapper/mpathcp3 /dev/mapper/mpathcp4 /dev/mapper/mpathcp5
Source: (StackOverflow)
I use mdadm create to create a soft RAID device to store some private documents.
I find that when I reboot my system the RAID device will be assemble automatically.
I want assemble the device manually.
I have remove all the mdadm command from rc.sysinit rc.d/* but there's no effect. Please give me a hand.
OS: Centos6.5
Source: (StackOverflow)
I'm using Ubuntu 13.10 and trying to create a RAID 5 array across 3 identical disks connected to SATA ports on the motherboard. I've followed every guide and and used both the built-in Disks GUI app and mdadm at the command line, and despite everything I cannot get the array to persist after reboot.
I create the array with the following command:
root@zapp:~# mdadm --create /dev/md/array --chunk=512 --level=5 \
--raid-devices=3 /dev/sda /dev/sdb /dev/sdd
Then I watch /proc/mdstat for awhile while it syncs, until I get this:
Personalities : [linear] [multipath] [raid0] [raid1] [raid6] [raid5] [raid4] [raid10]
md127 : active raid5 sda1[0] sdd1[3] sdb1[1]
1953262592 blocks super 1.2 level 5, 512k chunk, algorithm 2 [3/3] [UUU]
unused devices: <none>
To update the mdadm config file, I run the following:
root@zapp:~# /usr/share/mdadm/mkconf > /etc/mdadm/mdadm.conf
This adds the essential line to my config file:
ARRAY /dev/md/array metadata=1.2 UUID=0ad3753e:f0177930:8362f527:285d76e7 name=zapp:array
Everything seems correct, but when I reboot, the array is gone!
Source: (StackOverflow)
The title says it all.
I have a 3 partitions mdadm raid 5 on ubuntu.
Now I added a 4th partition.
All partitions cover the full physical disk, each disk is 4 TB in size.
The Filesystem in use is ext4.
After mdadm growing the raid 5 the wiki says to make an fsck check and then resize
Do I have to wait for the mdadm reshape to finish for the resize2fs to work?
If not it doesn't seem to work.
the raid is unmounted of course.
I did the fsck -f check.
ran resize2fs on the raid
but mdadm -D /dev/md0 still shows 4 disks with Array size 8 TB and dev size 4 TB.
fdisk -l also shows only a size of 8 TB.
Did i do something wrong?
How can i resize the filesystem to include my 4th disk?
fdisk -l output:
Disk /dev/sdb: 3.7 TiB, 4000787030016 bytes, 7814037168 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 4096 bytes
I/O size (minimum/optimal): 4096 bytes / 4096 bytes
Disklabel type: gpt
Disk identifier: E434C200-63C3-4CB8-8097-DD369155D797
Device Start End Sectors Size Type
/dev/sdb1 2048 7814035455 7814033408 3.7T Linux RAID
Disk /dev/sdd: 3.7 TiB, 4000787030016 bytes, 7814037168 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 4096 bytes
I/O size (minimum/optimal): 4096 bytes / 4096 bytes
Disklabel type: gpt
Disk identifier: CAD9D9DA-1C3B-4FC2-95BD-A5F0B55DE313
Device Start End Sectors Size Type
/dev/sdd1 2048 7814035455 7814033408 3.7T Linux RAID
Disk /dev/sdc: 3.7 TiB, 4000787030016 bytes, 7814037168 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 4096 bytes
I/O size (minimum/optimal): 4096 bytes / 4096 bytes
Disklabel type: gpt
Disk identifier: 090E94F6-A461-4B27-BCDF-5B49EC6AFC84
Device Start End Sectors Size Type
/dev/sdc1 2048 7814035455 7814033408 3.7T Linux RAID
Disk /dev/sde: 3.7 TiB, 4000787030016 bytes, 7814037168 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 4096 bytes
I/O size (minimum/optimal): 4096 bytes / 4096 bytes
Disklabel type: gpt
Disk identifier: A0285071-2C16-42B4-8567-32CE98147A93
Device Start End Sectors Size Type
/dev/sde1 2048 7814035455 7814033408 3.7T Linux RAID
Disk /dev/md0: 7.3 TiB, 8001301774336 bytes, 15627542528 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 4096 bytes
I/O size (minimum/optimal): 524288 bytes / 1572864 bytes
mdadm -D /dev/md0 output
/dev/md0:
Version : 1.2
Creation Time : Thu Jan 7 08:23:57 2016
Raid Level : raid5
Array Size : 7813771264 (7451.79 GiB 8001.30 GB)
Used Dev Size : 3906885632 (3725.90 GiB 4000.65 GB)
Raid Devices : 4
Total Devices : 4
Persistence : Superblock is persistent
Intent Bitmap : Internal
Update Time : Mon Jan 11 08:10:47 2016
State : clean, reshaping
Active Devices : 4
Working Devices : 4
Failed Devices : 0
Spare Devices : 0
Layout : left-symmetric
Chunk Size : 512K
Reshape Status : 47% complete
Delta Devices : 1, (3->4)
Name : NAS:0 (local to host NAS)
UUID : 69ba4b0e:a2427b2a:121cc4e0:5461a8fb
Events : 10230
Number Major Minor RaidDevice State
0 8 33 0 active sync /dev/sdc1
1 8 49 1 active sync /dev/sdd1
3 8 65 2 active sync /dev/sde1
4 8 17 3 active sync /dev/sdb1
Source: (StackOverflow)
I am working on a script to install a array raid5. I am having trouble with inserting auto=yes when the script ask: if I want to continue creating array. I tried --auto=yes (http://www.linuxmanpages.com/man8/mdadm.8.php) but very unsure where to place it.
#!/bin/bash
mdadm mdadm --create --verbose /dev/md0 --level=5 --raid-devices=3 /dev/sdc1 /dev/sdd1 /dev/sde1 --spare-devices=1 /dev/sdf1
if [ $? -eq 0 ]; then
echo OK
else
echo FAIL
fi
Source: (StackOverflow)