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--- howtos:misc:software_raid_troubleshoot_howto [2016/11/27 11:48 (UTC)]
wisedraco
+++ howtos:misc:software_raid_troubleshoot_howto [2017/06/26 15:08 (UTC)]
wisedraco [Workarounds for incorrect raid devices naming]
@@ Line 1: / Line 1: @@
 <!-- Add your text below. We strongly advise to start with a Headline (see button bar above). -->
 ====== Software RAID troubleshoot ======
@@ Line 5: / Line 6: @@
 i be done with system, who,after lilo menu,\\
  write "loading kernel ............................." \\
+\\
 and then stops completely - nothing more.\\
+\\
 Initial configuration was:\\
 Intel DG965SS motherboard, core 2 duo 2.2 gHz E4500 CPU, 8 Gb RAM, \\
 x 1000 Gb Seagate SATA HDD ( as sda and sdb)\\
 ST1000DM003-1CH1\\
-, dvd-writer on sata4 port
+dvd-writer on sata4 port
 both seagate discs is partitioned as FD type ( linux autodetect raid) and 4 partitions ( mbr type) -
-   * 100 Gb root (md1)
+  * 100 Gb root (md1)
-  *  2 Gb swap (md2)
+  * 2 Gb swap (md2)
-  *  350 Gb /home (md3)
+  * 350 Gb /home (md3)
-  *  550 Gb /Second (md4)
+  * 550 Gb /Second (md4)
+\\
+\\
 cat /proc/mdstat :
@@ Line 37: / Line 40: @@
 unused devices: <none>
 </code>
+\\
+\\
 mdadm -Es :
@@ Line 61: / Line 65: @@
 Then i do massive system update via slackpkg update-all, including kernel update too.\\
 check lilo.conf, restart - all looks ok. then i decide to upgrade system to 14.2 via the same slackpkg \\
-( looks like live on macos is too boring, too predictable - all work, and so on...:D )
+( looks like live on macos is too boring, too predictable - all work, and so on...:D )\\
 always, i check lilo.conf, check the new kernel is named right, have no old kernel for backup - \\
 only one entry in lilo ( who was not good thing at all! ), and do reboot.
@@ Line 318: / Line 322: @@
 that was, in a most, all of story.
 yet, there is some another workarounds of that situation.
+\\
+\\
+ ===== Workarounds for incorrect raid devices naming =====
+  - 1. Using UUID in lilo ( i do not check this), and in fstab for mounting partitions.
+ do a
+<code>
+ls /dev/disk/by-uuid/
+</code>
+or better, go in that location with midnight commander, and youl see, there is a "files" named as numbers -
+that was the raid array disk uuid - and symlink to /dev/mdx.
+for automate info feed into fstab you can use this way:
+<code>
+cd /dev/disk/by-uuid
+ls -d -l $PWD/* >> /etc/fstab
+</code>
+after that you must immediately edit /etc/fstab and make in a right way, otherwise you may have problems with mounting in next boot...
+<code>
+/dev/md2         swap             swap        defaults         0   0
+/dev/md1         /                ext4        defaults         1   1
+##/dev/md3         /home            ext4        defaults         1   2
+/dev/disk/by-uuid/ef92814a-2db1-4d47-8d70-4c5a8d56e287   /home            ext4        defaults         1   2
+/dev/md4         /Second          ext4        defaults         1   2
+#/dev/cdrom      /mnt/cdrom       auto        noauto,owner,ro,comment=x-gvfs-show 0   0
+/dev/fd0         /mnt/floppy      auto        noauto,owner     0   0
+devpts           /dev/pts         devpts      gid=5,mode=620   0   0
+proc             /proc            proc        defaults         0   0
+tmpfs            /dev/shm         tmpfs       defaults         0   0
+</code>
+<note important>take a note!
+disk UUID by
+/dev/disk/by-uuid/
+and that one, who you get via
+<code>
+mdadm -D
+mdadm -Db
+mdadm -Es
+</code>
+differ, not the same!!!
+ in fstab ( lilo too?) you must use UID from /dev/disk/by-uuid/  !</note>
+  - 2. Using initramd.
+<code>
+#
+# mkinitrd_command_generator.sh revision 1.45
+#
+# This script will now make a recommendation about the command to use
+# in case you require an initrd image to boot a kernel that does not
+# have support for your storage or root filesystem built in
+# (such as the Slackware 'generic' kernels').
+# A suitable 'mkinitrd' command will be:
+#/usr/share/mkinitrd/
+mkinitrd -c -k 3.2.29 -f ext4 -r /dev/md1 -m mbcache:jbd2:ext4 -R -u -o /boot/initrd.gz
+</code>
+\\
+\\
+rightly edited mdadm.conf then must be copied in/boot/tree??? before you run this mkinitrd conf.\\
+after you run that mkinitrd, you must update lilo.
+====== Useful commands in this case ======
+show raid array info:
+<code>
+mdadm -Es
+</code>
+Assemble RAID array based on mdadm.conf
+<code>
+mdadm -As
+</code>
+show array info:
+<code>
+mdadm -D /dev/md127
+</code>
+show defined array another info:
+<code>
+mdadm -Db /dev/md127
+</code>
+show scsi devices info:
+<code>
+lsscsi
+</code>
+show assembled raid arrays status:
+<code>
+cat /proc/mdstat
+</code>
+show UUID info about discs ( or RAID arrays) in system:
+<code>
+ls /dev/disk/by-uuid/
+</code>
+<code>
+dmesg |grep md
+</code>
+re-run lilo, when booted from another source.
+<code>
+chroot /mnt/hd /sbin/lilo -v 3
+</code>
+stop named RAID array:
+<code>
+mdadm --stop /dev/md127
+</code>
+kernel options:
+<code>
+$kernelname raid=noautodetect md=1, /dev/sda1,/dev/sdb1
+</code>
+turn on not to autodetect RAID arrays, and define raid array /dev/md1, from two partitions ( members? )
+====== Useful Links: ======
+  * [[http://www.linuxquestions.org/questions/slackware-14/repair-lilo-on-software-raid1-4175593663/]]
+  * [[https://bugzilla.redhat.com/show_bug.cgi?id=606481]]
+  * [[https://www.linux.org.ru/forum/admin/13033496?lastmod=1479927790872]] (in russian )
+  * [[https://raid.wiki.kernel.org/index.php/Linux_Raid]]
+  * [[https://www.kernel.org/doc/Documentation/md.txt]]
+====== Sources ======
+Originally written by  --- //[[wiki:user:wisedraco|John Ciemgals]] 2016/11/28 04:50//
+Rewrited with used materials from "Links" and LinuxQuestions.org Slackware forum, especially user bassmadrigal and bormant from linux.org.ru help --- //[[wiki:user:wisedraco|John Ciemgals]] 2016/11/28 09:15//
+<!-- Please do not modify anything below, except adding new tags.-->
+{{tag>software raid raid1 /dev/md127 enumeration broken linux slackware author_wisedraco}}

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