[CentOS] Booting Software RAID

[Ljubomir Ljubojevic]

On 01/27/2014 04:26 PM, Matt wrote:
>> I installed Centos 6.x 64 bit with the minimal ISO and used two disks
>> in RAID 1 array.
>>
>> Filesystem      Size  Used Avail Use% Mounted on
>> /dev/md2         97G  918M   91G   1% /
>> tmpfs            16G     0   16G   0% /dev/shm
>> /dev/md1        485M   54M  407M  12% /boot
>> /dev/md3        3.4T  198M  3.2T   1% /vz
>>
>> Personalities : [raid1]
>> md1 : active raid1 sda1[0] sdb1[1]
>>        511936 blocks super 1.0 [2/2] [UU]
>> md3 : active raid1 sda4[0] sdb4[1]
>>        3672901440 blocks super 1.1 [2/2] [UU]
>>        bitmap: 0/28 pages [0KB], 65536KB chunk
>> md2 : active raid1 sdb3[1] sda3[0]
>>        102334336 blocks super 1.1 [2/2] [UU]
>>        bitmap: 0/1 pages [0KB], 65536KB chunk
>> md0 : active raid1 sdb2[1] sda2[0]
>>        131006336 blocks super 1.1 [2/2] [UU]
>>
>> My question is if sda one fails will it still boot on sdb?  Did the
>> install process write the boot sector on both disks or just sda?  How
>> do I check and if its not on sdb how do I copy it there?
>
> Based on input from everyone here I am thinking of an alternate setup.
>   Single small inexpensive 64GB SSD used as /boot, / and swap.  Putting
> /vz on software RAID1 array on the two 4TB drives.  I can likely just
> zip tie the SSD in the 1u case somewhere since I have no more drive
> bays.  Does this seem like a better layout?

As long as you have duplicate SSD as backup and regularly backup /boot 
to that other SSD, it should be OK. Loosing SSD and /boot with new 
kernels would be a mayor problem for you, you would need to recreate them.


Ljubomir Ljubojevic
(Love is in the Air)
PL Computers
Serbia, Europe

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