Ruslan Sivak wrote:
> Les Mikesell wrote:
>> Ruslan Sivak wrote:
>>> B.J. McClure wrote:
>>>>
>>>>> I would like to set up CentOS on 4 SATA hard drives that I would
>>>>> like to
>>>>> configure in RAID10. I read somewhere that Raid10 support is in the
>>>>> latest kernel, but I can't seem to get anaconda to let me create
>>>>> it. I
>>>>> only see raid 0, 1, 5, and 6.
>>>>>
>>>>> Even when I tried to set up raid5 or raid1, it would not let me put
>>>>> the
>>>>> /boot partition on it, and I though that this was now possible.
>>>>>
>>>>> Is it possible for me to set up the configuration I'm looking for?
>>>>>
>>>>> Russ
>>>>>
>>>> Cannot speak to raid 10 but have been running 4.4 an 5.0 with raid 1
>>>> and /boot partition on md0 for some time. Have not seen the issue
>>>> you refer to.
>>>>
>>>> bj
>>>>
>>>>
>>>
>>> Well as far as Raid10, it's not even an option for the installer. If
>>> I do select raid1 for the entire array, I only get the space of 3 of
>>> the 4 drives, and the installer still complains that I cannot put
>>> boot on a raid system.
>>> Is there a how-to somewhere on getting this to work?
>>
>> I don't know if the installer will let you do it, but you are supposed
>> to be able to create RAID1 devices, then stripe across them by using
>> those md devices in a RAID0. I'm not sure if there is any advantage
>> to that over using LVM to combine the RAID1 devices though.
>> Personally I prefer to use RAID1 and deal with the space on separate
>> mounted partitions since it permits recovering the data from any
>> single drive but if I had to have a larger chunk I'd probably put
>> /boot on a RAID1 and the rest in mirrored partitions combined in LVM.
>
> I just did an install where i set up boot on raid1 (sda1,sdb1 with sdc1
> and sdd1 as spares), swap on raid0 (sda2, sdb2, sdc2, sdd2) and then
> created 2 LVM partitions /dev/md2 (raid1 of sda3 and sdb3) and /dev/md3
> (raid1 of sdc3 and sdd3). I then combine the 2 partitions in LVM and
> put root on it.
> Everything installed fine, but got stuck at the grub prompt.
Did you try to boot the install CD in rescue mode at that point? Grub
doesn't know much about raid and only works because you can treat the
mirrors as a singled disk. You should have been able to reinstall grub
on /dev/sda (and again on /dev/sdb) from the rescue boot to fix things.
> I am now trying to set up raid10 manually by using mdadm, but it gives
> me an error, and when looking at dmesg, it says "md: personality for
> level 10 is not loaded!".
> Does this mean that the currently compiled in kernel doesn't support
> raid10?
Can you build your RAID1 sets first, then combine those md devices in a
RAID0?
--
Les Mikesell
lesmikesell at gmail.com