[prev in list] [next in list] [prev in thread] [next in thread] 

List:       openbsd-misc
Subject:    Re: proper way to grow softraid partition
From:       kasak <kasak () kasakoff ! net>
Date:       2021-10-31 10:00:33
Message-ID: 3a6ca783-b692-5224-5000-68ca226784fd () kasakoff ! net
[Download RAW message or body]


29.10.2021 15:33, Nick Holland пишет:
> On 10/27/21 1:11 PM, kasak wrote:
>> Hello misc!
>>
>> I want to replace my two 2TB hdd, joined in raid1.
>>
>> I have two 4TB drives, and I want to replace smaller drives with them.
>>
>> it wouldn't be a problem, if i had some spare sata ports, but in my pc i
>> have only one left.
>>
>> So, I can attach only one of this 4 tb drives at the same time.
>>
>>
>> I think, maybe I can attach new 4 tb drive to old raid as a third
>> volume, wait for it "repair",
>
> Unfortunately, unless something changed when I wasn't looking, you can't
> change the number of drives in a softraid RAID1 after creation.  I really
> wish you could.
>
>> and then remove 2 tb drives, add one more 4 tb and "repair" raid again.
>>
>> I don't know, will this operation actually grow my partition, or it is a
>> bad idea from the beginning?
>
> nope, you would end up with a 2T RAID partition on a 4G drive. Which is
> fine, except you didn't achieve your goal.
>
>> Alternate, can i create raid 1 volume from just one drive, rsync files
>> between raids and after add another disk?
>
> Again, you can't change the number of drives in a softraid RAID1 set 
> after
> creation.  And you can't change the size of a softraid partition.
>
> What I would (and have) done is this, assuming this is your only computer
> available:
> * extract both your 2T drives.
> * insert both 4T drives, build a RAID1 set.
> * Insert ONE of the old 2T drives and ONE of the 4T drives into your 
> system.
> On boot, you end up with two degraded arrays...but that will work for 
> your
> purposes!
> * Copy the data from the old disks to the new disks
> * Change fstab
> * Remove the old 2T disk, and replace with the 4T disk left over, rebuild
> the degraded array onto the 4T disk.
> * DONE!
>
> Now...since you have ONE spare port still, I'd actually cheat and remove
> one 2T disk, and put both new disks in place, build the array, and copy
> over. Fix fstab, remove the old 2T disk, done.
>
Thank you very much for detailed explanation!
I will go this way!
> HOWEVER, something else to consider -- from later messages, sounds 
> like you
> have a non-RAID boot drive and RAID data drives.  I SUSPECT you could 
> build
> out your new 4T array as a bootable softraid and move your boot drive 
> data
> AND the 2T of old data all to the one 4T array and still have a lot of 
> new
> space (a basic OpenBSD install is barely noticeable in a 4T disk!).  Now
> you have redundancy in both boot and data, and one less disk, which 
> will be
> a small power reduction, and one less point of failure.
>
> Nick.
>
>

[prev in list] [next in list] [prev in thread] [next in thread]