Slack 11 and 12 RAID questions
Hey all,
During all my time with Slackware 11 I've build my raids during install using the "good" old raidtools. It's worked like a charm. Now with Slackware 12 I no longer have raidtools available during install, so I'm forced to use mdadm instead. So far I like it quite well. It's a heck of a lot easier to get those raids up and running without having to write a lot of stuff in /etc/raidtab. :) But! How do I go about managing my raids now? I've read that mdadm doesn't really need a .conf file, but what happens then if a disk fails and I need to rebuild? Any and all mdadm tricks are more than welcome. What's considered good practice when maintaining raids using mdadm. Regards, Thomas |
Ok, after my initial success with the whole mdadm RAID creation, I've run into a boot issue.
Slackware 12 RAID level 1 / on /dev/md0 /var on /dev/md1 /home on /dev/md2 When I switch from hugesmp.s to generic, it wont boot. I've done the whole lilo/mkinitrd dance: $ mkinitrd -c -k 2.6.21.5 -m ext3 -f ext3 -r /dev/md0 $ lilo And I have of course added the appropriate information to lilo.conf. It starts well with the classic lilo menu, where the new generic kernel shows up. I select it, and booting begins. Then after a while it reaches a point where this happens: mount: Mounting /dev/md0 on /mnt failed ERROR: No /sbin/init found on rootdev And then it just sits there. I never had this issue with Slackware 11 using raidtools and running the exact same raidsetup. I must be doing something wrong, I just can figure out what. It looks as if /dev/md0 doesn't exist during boot, and seeing as / is mounted on /dev/md0, that would indeed be a problem. Any advice? :) Thomas |
Are there any additional modules you have to include when running mkinitrd to support the raid. You've only added support for a couple of filesystems.
Cheers. |
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Anybody? Thomas |
This page describes (in german) how to modify mkinitrd and your initrd's "init" script so that it builds your RAID array on boot: http://apropos.wordpress.com/2007/07...-raid-und-lvm/
But this support for software-RAID should really be added to the Slackware mkinitrd package in the next slackware-current round. Eric |
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# # Multi-device support (RAID and LVM) # CONFIG_MD=y CONFIG_BLK_DEV_MD=y CONFIG_MD_LINEAR=y CONFIG_MD_RAID0=y CONFIG_MD_RAID1=y CONFIG_MD_RAID10=y CONFIG_MD_RAID456=y CONFIG_MD_RAID5_RESHAPE=y CONFIG_MD_MULTIPATH=y CONFIG_MD_FAULTY=m CONFIG_BLK_DEV_DM=y # CONFIG_DM_DEBUG is not set CONFIG_DM_CRYPT=y CONFIG_DM_SNAPSHOT=m CONFIG_DM_MIRROR=m CONFIG_DM_ZERO=m CONFIG_DM_MULTIPATH=m CONFIG_DM_MULTIPATH_EMC=m Does that not mean that RAID support is build into the kernel already? Or? Regards, Thomas |
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As far as I can see, it looks as if the problem is due to mdadm? /dev/md0 simply does not exist at this point in time, because it hasn't been assembled by mdadm yet? How this worked with raidtools is beyond me. I do though agree with you: This REALLY should be fixed as fast as possible. :) Thomas |
Hmm, seeing as it works with the huge kernel, couldn't I just compile my own with all the relevant modules loaded in the kernel?
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Cheers. |
OK after conferring with Patrick, PiterPUNK and Stuart Winter, this is the verdict:
Software RAID will work out of the box in Slackware (no initrd needed) if the following conditions are met: - The raid drivers are compiled into the kernel (no modules!) - The partition types are set to "Linux RAID Autodetect" (type 'fd') Note that with RAID drivers as modules, the RAID autodetection by the kernel will fail. Cheers, Eric |
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Slackware and its community is miles above and beyond what most other distros offer. I will compile a new kernel and report back. :) Sincerely, Thomas |
Might I add a shameless plug to my Raid Howto. It may still be of some use to you.
http://www.userlocal.com/articles/ra...ackware-12.php |
Just to report back: It worked like a charm!
:) Thomas |
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