[CentOS] kickstart raid disk partitioning

Roberto Nunnari roberto.nunnari at supsi.ch
Fri Nov 19 04:32:15 EST 2010


Digimer ha scritto:
> On 11/18/2010 01:11 PM, Roberto Nunnari wrote:
>> Hello.
>>
>> A couple of years ago I installed two file-servers
>> using kickstart. The server has two 1TB sata disks
>> with two software raid1 partitions as follows:
>>
>> # cat /proc/mdstat
>> Personalities : [raid1]
>> md1 : active raid1 sdb4[1] sda4[0]
>>         933448704 blocks [2/2] [UU]
>> md0 : active raid1 sdb1[1] sda2[2](F)
>>         40957568 blocks [2/1] [_U]
>>
>>
>> Now the drives are starting to be failing and next week I'll
>> backup /homes, reinstall OS with kickstart, and finally
>> restore /homes.
>>
>> There's a problem with how the kickstart process partitions
>> the disks, though. As you may have noticed above, md0 is made
>> up of sdb1 and sda2.
>>
>> Could anybody help me understand how to make the partitions
>> on the two drives identical still using kickstart?
>>
>> Here's the relevant part from the kickstart file:
>>
>> zerombr yes
>> clearpart --all --initlabel
>> bootloader --location=mbr
>> part /boot --fstype ext3 --size 250 --asprimary --ondisk sda
>> part swap --size 2048 --asprimary --ondisk sda
>> part raid.01 --size 40000 --asprimary --ondisk sda
>> part raid.03 --size 1 --grow --asprimary --ondisk sda
>> part /boot2 --fstype ext3 --size 250 --asprimary --ondisk sdb
>> part swap --size 2048 --asprimary --ondisk sdb
>> part raid.02 --size 40000 --asprimary --ondisk sdb
>> part raid.04 --size 1 --grow --asprimary --ondisk sdb
>> raid / --level=1 --device=md0 --fstype ext3 raid.01 raid.02
>> raid /home --level=1 --device=md1 --fstype ext3 raid.03 raid.04
>>
>> ..but here's the produced partitioning on the two drives:
>>
>> # parted /dev/sda print
>> Disk geometry for /dev/sda: 0.000-953869.710 megabytes
>> Disk label type: msdos
>> Minor    Start       End     Type      Filesystem  Flags
>> 1          0.031    251.015  primary   ext3        boot
>> 2        251.016  40248.786  primary   ext3        raid
>> 3      40248.787  42296.132  primary   linux-swap
>> 4      42296.133 953867.219  primary   ext3        raid
>>
>> # parted /dev/sdb print
>> Disk geometry for /dev/sdb: 0.000-953869.710 megabytes
>> Disk label type: msdos
>> Minor    Start       End     Type      Filesystem  Flags
>> 1          0.031  39997.771  primary   ext3        boot, raid
>> 2      39997.771  42045.117  primary   linux-swap
>> 3      42045.117  42296.132  primary   ext3
>> 4      42296.133 953867.219  primary   ext3        raid
>>
>>
>> I'm not asking because I'm picky, but just because, it would
>> have made my life easier to fix bad blocks on disks by
>> dd from good block on disk1 to bad block on disk2, and as
>> next week I'll reinstall, I'd prefer to do it the right way.
>>
>> Some more bits about my environment:
>>
>> # cat /etc/redhat-release
>> CentOS release 4.8 (Final)
>>
>> # uname -rms
>> Linux 2.6.9-89.0.18.ELsmp i686
>>
>> Thank you and best regards.
>> Robi
> 
> I've got a fairly simple script in a kickstart file I use[1] that 
> handles RAID 1 and RAID 5 partitioning. Perhaps it would help? Here is 
> the relevant snippet:
> 
> zerombr
> clearpart --all --initlabel --drives=sda,sdb
> ignoredisk --only-use=sda,sdb
> bootloader  --location=mbr --driveorder=sda,sdb --append="crashkernel=auto"
> 
> # /boot
> part raid.01 --ondisk=sda --asprimary --size=256
> part raid.02 --ondisk=sdb --asprimary --size=256
> # /
> part raid.11 --ondisk=sda --asprimary --size=40960
> part raid.12 --ondisk=sdb --asprimary --size=40960
> # <swap>
> part raid.21 --ondisk=sda --asprimary --size=4096
> part raid.22 --ondisk=sdb --asprimary --size=4096
> 
> # Format /boot and /.
> raid /boot --fstype=ext3 --level=1 --device=md0 raid.01 raid.02
> raid /     --fstype=ext3 --level=1 --device=md1 raid.11 raid.12
> raid swap  --fstype=swap --level=1 --device=md2 raid.21 raid.22
> 
> The kickstart script above is specifically for RHEL 6, but it came 
> nearly unadapted from an older CentOS 4 kickstart script. The only line 
> that might be an issue is: "crashkernel=auto".
> 
> hth,
> 
> Digimer
> 
> 1. http://wiki.alteeve.com/files/an-cluster/ks/generic_server_rhel6.ks

Thank you for your reply.

Does that kickstart effectly produces a partitioning that is
exactly the same on both disks? Because that is the problem
I'm facing: the partitioning produced by the kickstart
is different on the two drives.

Also, why did you put /boot and swap in raid? Was it for
obtaining identical partitioning on both drives?
For swap, the kernel already does performance optimization
when swap partitions are on different drives, and /boot..
I always tended to keep /boot be as simple as possible, to avoid
any problem during boot.. but maybe, these days with initramdisk
there's no more need for that..

Best regards.
Robi


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