[CentOS] preferred software RAID 10?
Rudi at SoftDux.com
Thu Jul 17 22:46:07 UTC 2008
Ross S. W. Walker wrote:
> Rudi Ahlers wrote:
>> John R Pierce wrote:
>>> Rudi Ahlers wrote:
>>>> And then, how do I setup the partitioning? Do I setup /boot on a
>>>> separate RAID "partition"? If so, what happens if I want to replace
>>>> the 1st 2 HDD's with bigger ones?
>>> each partition is raided seperately with mdadm.... you could make the
>>> whole thing one LVM partition thats raid10, then use LVM to dice it up
>>> into file systems.
>>> if you have 4 drives and are doing software raid10, you won't be
>>> swapping drives with different sizes without a WHOLE lotta pain.
>> Ok, so how do I do this? Let's say I have 4x 160GB HDD's now, and plan
>> on replacing them with 4x 500GB HDD's in the future?
> Personally I would never put an OS install on a higher RAID then RAID1,
> because it gets too messy to upgrade like you suggested.
So you're suggesting that I keep the OS separate from the data? But what
happens if both the 1st 2 drives with the OS fails, or needs to be replaced?
>> What setup would help with a upgrade in the future?
>>> /boot shouldn't be mirrored, as the BIOS won't know how to boot it.
>>> leave /dev/sdb1 the same size as /dev/sda1 and call it /boot2 and try
>>> to remember to copy /boot to /boot2 each time you update the kernel.
>> I understand this, but how do you boot from /boot2 on the
>> second HDD if the 1st have failed?
> Could you not get a system that had 2 drives for the OS and 4 drives
> for data?
nope, unfortunately not. It's a 2U rackmount chassis with space for only
4 HDD's. I have been thinking about installing the OS onto a USB memory
stick, but have never actually got as far as trying to figure out how
> I have setup 4 disk RAID10 systems before, but they were never
> intended to be upgraded (in place at least).
> I can forward a couple of recipes, but let me first say that to do
> it from the CentOS install media requires 2 RAID1s and LVM striping
> because the RAID10 option isn't on the media, but it is functionally
> equivalent both in useable space and performance.
Please share your recipes, I'd like to give it a try :)
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