Failing to grow raid10 with one larger disk

Failing to grow raid10 with one larger disk

[Asif Iqbal]

Replaced one of the 6 72G disks from raid10 with a 300G disk.

But failing to grow the md10

# mdadm --grow /dev/md10 --size max
mdadm: raid10 array /dev/md10 cannot be reshaped.

What gives?

--
Asif Iqbal
PGP Key: 0xE62693C5 KeyServer: pgp.mit.edu
A: Because it messes up the order in which people normally read text.
Q: Why is top-posting such a bad thing?

Re: Failing to grow raid10 with one larger disk

[Mathias Burén]

On 25 January 2013 00:33, Asif Iqbal <vadud3@gmail.com> wrote:
> Replaced one of the 6 72G disks from raid10 with a 300G disk.
>
> But failing to grow the md10
>
> # mdadm --grow /dev/md10 --size max
> mdadm: raid10 array /dev/md10 cannot be reshaped.
>
> What gives?
>
> --
> Asif Iqbal
> PGP Key: 0xE62693C5 KeyServer: pgp.mit.edu
> A: Because it messes up the order in which people normally read text.
> Q: Why is top-posting such a bad thing?
> --
> To unsubscribe from this list: send the line "unsubscribe linux-raid" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html

What did you expect?

Mathias

Re: Failing to grow raid10 with one larger disk

[Asif Iqbal]

On Thu, Jan 24, 2013 at 7:43 PM, Mathias Burén <mathias.buren@gmail.com> wrote:
> On 25 January 2013 00:33, Asif Iqbal <vadud3@gmail.com> wrote:
>> Replaced one of the 6 72G disks from raid10 with a 300G disk.
>>
>> But failing to grow the md10
>>
>> # mdadm --grow /dev/md10 --size max
>> mdadm: raid10 array /dev/md10 cannot be reshaped.
>>
>> What gives?
>>
>> --
>> Asif Iqbal
>> PGP Key: 0xE62693C5 KeyServer: pgp.mit.edu
>> A: Because it messes up the order in which people normally read text.
>> Q: Why is top-posting such a bad thing?
>> --
>> To unsubscribe from this list: send the line "unsubscribe linux-raid" in
>> the body of a message to majordomo@vger.kernel.org
>> More majordomo info at  http://vger.kernel.org/majordomo-info.html
>
> What did you expect?
>

I was hoping to grow the size of the raid10.

I was following this link

https://raid.wiki.kernel.org/index.php/Growing#Expanding_existing_partitions

> Mathias



--
Asif Iqbal
PGP Key: 0xE62693C5 KeyServer: pgp.mit.edu
A: Because it messes up the order in which people normally read text.
Q: Why is top-posting such a bad thing?
--
To unsubscribe from this list: send the line "unsubscribe linux-raid" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html

Re: Failing to grow raid10 with one larger disk

[Brad Campbell]

On 25/01/13 09:02, Asif Iqbal wrote:
> I was hoping to grow the size of the raid10. I was following this link 
> https://raid.wiki.kernel.org/index.php/Growing#Expanding_existing_partitions

Re-read the second sentence on the first line of that page.

Re: Failing to grow raid10 with one larger disk

[Asif Iqbal]

On Thu, Jan 24, 2013 at 8:09 PM, Brad Campbell <brad@fnarfbargle.com> wrote:
> On 25/01/13 09:02, Asif Iqbal wrote:
>>
>> I was hoping to grow the size of the raid10. I was following this link
>> https://raid.wiki.kernel.org/index.php/Growing#Expanding_existing_partitions
>
>
> Re-read the second sentence on the first line of that page.

doh! so I can only grow raid level 1/4/5/6

ok, can you suggest how can I increase the /dir (/dev/md10) with bigger disks?

I already backed up the data.

does linux software raid allow disks of different sizes in raid10? I
did not see much discussion
of raid level 10 in that wiki page.

--
Asif Iqbal
PGP Key: 0xE62693C5 KeyServer: pgp.mit.edu
A: Because it messes up the order in which people normally read text.
Q: Why is top-posting such a bad thing?

Re: Failing to grow raid10 with one larger disk

[Adam Goryachev]

On 25/01/13 12:22, Asif Iqbal wrote:
> On Thu, Jan 24, 2013 at 8:09 PM, Brad Campbell <brad@fnarfbargle.com> wrote:
>> On 25/01/13 09:02, Asif Iqbal wrote:
>>> I was hoping to grow the size of the raid10. I was following this link
>>> https://raid.wiki.kernel.org/index.php/Growing#Expanding_existing_partitions
>>
>> Re-read the second sentence on the first line of that page.
> doh! so I can only grow raid level 1/4/5/6
>
> ok, can you suggest how can I increase the /dir (/dev/md10) with bigger disks?
>
> I already backed up the data.
>
> does linux software raid allow disks of different sizes in raid10? I
> did not see much discussion
> of raid level 10 in that wiki page.

From my understanding, there are two methods:
1) Create new RAID10, dd old RAID10 to new one, expand
filesystem/lvm/whatever is on the RAID10
2) Don't use RAID10, use RAID1 + linear. Don't increase the size of
members, only add additional pairs at the end of the linear array.
3) The one exception to 2 is that you can expand the size of the last
pair, but this is somewhat tricky. I've done this successfully twice,
but I doubt you really want to be using linear anyway.

Regards,
Adam

-- 
Adam Goryachev
Website Managers
www.websitemanagers.com.au

Re: Failing to grow raid10 with one larger disk

[Asif Iqbal]

On Thu, Jan 24, 2013 at 8:32 PM, Adam Goryachev
<mailinglists@websitemanagers.com.au> wrote:
> On 25/01/13 12:22, Asif Iqbal wrote:
>> On Thu, Jan 24, 2013 at 8:09 PM, Brad Campbell <brad@fnarfbargle.com> wrote:
>>> On 25/01/13 09:02, Asif Iqbal wrote:
>>>> I was hoping to grow the size of the raid10. I was following this link
>>>> https://raid.wiki.kernel.org/index.php/Growing#Expanding_existing_partitions
>>>
>>> Re-read the second sentence on the first line of that page.
>> doh! so I can only grow raid level 1/4/5/6
>>
>> ok, can you suggest how can I increase the /dir (/dev/md10) with bigger disks?
>>
>> I already backed up the data.
>>
>> does linux software raid allow disks of different sizes in raid10? I
>> did not see much discussion
>> of raid level 10 in that wiki page.
>
> From my understanding, there are two methods:
> 1) Create new RAID10, dd old RAID10 to new one, expand
> filesystem/lvm/whatever is on the RAID10

I like this method. However, can I have raid10 with disks of multiple sizes?
( for my case 2 76G and 4 300G )


> 2) Don't use RAID10, use RAID1 + linear. Don't increase the size of
> members, only add additional pairs at the end of the linear array.
> 3) The one exception to 2 is that you can expand the size of the last
> pair, but this is somewhat tricky. I've done this successfully twice,
> but I doubt you really want to be using linear anyway.
>
> Regards,
> Adam
>
> --
> Adam Goryachev
> Website Managers
> www.websitemanagers.com.au
>



--
Asif Iqbal
PGP Key: 0xE62693C5 KeyServer: pgp.mit.edu
A: Because it messes up the order in which people normally read text.
Q: Why is top-posting such a bad thing?

Re: Failing to grow raid10 with one larger disk

[Asif Iqbal]

On Thu, Jan 24, 2013 at 8:56 PM, Asif Iqbal <vadud3@gmail.com> wrote:
> On Thu, Jan 24, 2013 at 8:32 PM, Adam Goryachev
> <mailinglists@websitemanagers.com.au> wrote:
>> On 25/01/13 12:22, Asif Iqbal wrote:
>>> On Thu, Jan 24, 2013 at 8:09 PM, Brad Campbell <brad@fnarfbargle.com> wrote:
>>>> On 25/01/13 09:02, Asif Iqbal wrote:
>>>>> I was hoping to grow the size of the raid10. I was following this link
>>>>> https://raid.wiki.kernel.org/index.php/Growing#Expanding_existing_partitions
>>>>
>>>> Re-read the second sentence on the first line of that page.
>>> doh! so I can only grow raid level 1/4/5/6
>>>
>>> ok, can you suggest how can I increase the /dir (/dev/md10) with bigger disks?
>>>
>>> I already backed up the data.
>>>
>>> does linux software raid allow disks of different sizes in raid10? I
>>> did not see much discussion
>>> of raid level 10 in that wiki page.
>>
>> From my understanding, there are two methods:
>> 1) Create new RAID10, dd old RAID10 to new one, expand
>> filesystem/lvm/whatever is on the RAID10
>
> I like this method. However, can I have raid10 with disks of multiple sizes?
> ( for my case 2 76G and 4 300G )
>


This answered my question

http://www.spinics.net/lists/raid/msg17303.html


>
>> 2) Don't use RAID10, use RAID1 + linear. Don't increase the size of
>> members, only add additional pairs at the end of the linear array.
>> 3) The one exception to 2 is that you can expand the size of the last
>> pair, but this is somewhat tricky. I've done this successfully twice,
>> but I doubt you really want to be using linear anyway.
>>
>> Regards,
>> Adam
>>
>> --
>> Adam Goryachev
>> Website Managers
>> www.websitemanagers.com.au
>>
>
>
>
> --
> Asif Iqbal
> PGP Key: 0xE62693C5 KeyServer: pgp.mit.edu
> A: Because it messes up the order in which people normally read text.
> Q: Why is top-posting such a bad thing?



--
Asif Iqbal
PGP Key: 0xE62693C5 KeyServer: pgp.mit.edu
A: Because it messes up the order in which people normally read text.
Q: Why is top-posting such a bad thing?

Re: Failing to grow raid10 with one larger disk

[Chris Murphy]

On Jan 24, 2013, at 6:56 PM, Asif Iqbal <vadud3@gmail.com> wrote:
> 
> I like this method. However, can I have raid10 with disks of multiple sizes?
> ( for my case 2 76G and 4 300G )

Yes but it will only be as large as 2x the size of the lowest common denominator sized block device (disk or parition). There's simply no way you can have a raid10 array get bigger just be swapping out one of the disks with a larger disk. All of them must get bigger for the array to grow.

A RAID 10 is first a mirror, those two block devices must be the same size to be the same. And then to stripe, the mirrors must be the same size. So what you want to do is only workable by having all disks the same size.


Chris Murphy