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* How to use dm-cache-target?
@ 2013-03-11  2:28 majianpeng
  2013-03-11 10:31 ` thornber
  0 siblings, 1 reply; 6+ messages in thread
From: majianpeng @ 2013-03-11  2:28 UTC (permalink / raw)
  To: agk; +Cc: dm-devel

Hi all,
    I am trying to use dm-cache-target on raid5.But i met a question.

 Supposed: /dev/sdb1(5GB) is metadata; /dev/sdb2(20GB) is cache;/dev/md0 is raid5.

1:sutup my_cache
dmsetup create my_cache --table '0 41943040 cache /dev/sdb1 /dev/sdb2 /dev/md0 131072 1 writethrough default 0'

2:mkfs.ext4
mkfs.ext4 /dev/mapper/my_cache

3:mount
mount /dev/mapper/my_cache /media

4:the size of ext4 is 20GB,but the /dev/md0 is 4TB.

I think maybe my methods error. If so, how to do use?

BTW, for dm-cache is it support plug-and-play?

Thanks!
Jianpeng Ma

^ permalink raw reply	[flat|nested] 6+ messages in thread
* Re: How to use dm-cache-target?
  2013-03-11  2:28 How to use dm-cache-target? majianpeng
@ 2013-03-11 10:31 ` thornber
  2013-03-11 17:04   ` Darrick J. Wong
  0 siblings, 1 reply; 6+ messages in thread
From: thornber @ 2013-03-11 10:31 UTC (permalink / raw)
  To: device-mapper development

On Mon, Mar 11, 2013 at 10:28:07AM +0800, majianpeng wrote:
> Hi all,
>     I am trying to use dm-cache-target on raid5.But i met a question.
> 
>  Supposed: /dev/sdb1(5GB) is metadata; /dev/sdb2(20GB) is cache;/dev/md0 is raid5.
> 
> 1:sutup my_cache
> dmsetup create my_cache --table '0 41943040 cache /dev/sdb1 /dev/sdb2 /dev/md0 131072 1 writethrough default 0'

41943040 - This is 20G, you should use the size of /dev/md0 in sectors

Also I think your block size is way too big, try 2048 rather tha 131072.

> BTW, for dm-cache is it support plug-and-play?

No idea what you mean.

- Joe

^ permalink raw reply	[flat|nested] 6+ messages in thread
* Re: How to use dm-cache-target?
  2013-03-11 10:31 ` thornber
@ 2013-03-11 17:04   ` Darrick J. Wong
  2013-03-11 17:11     ` Zdenek Kabelac
  2013-03-12 13:27     ` thornber
  0 siblings, 2 replies; 6+ messages in thread
From: Darrick J. Wong @ 2013-03-11 17:04 UTC (permalink / raw)
  To: device-mapper development

On Mon, Mar 11, 2013 at 10:31:53AM +0000, thornber@redhat.com wrote:
> On Mon, Mar 11, 2013 at 10:28:07AM +0800, majianpeng wrote:
> > Hi all,
> >     I am trying to use dm-cache-target on raid5.But i met a question.
> > 
> >  Supposed: /dev/sdb1(5GB) is metadata; /dev/sdb2(20GB) is cache;/dev/md0 is raid5.
> > 
> > 1:sutup my_cache
> > dmsetup create my_cache --table '0 41943040 cache /dev/sdb1 /dev/sdb2 /dev/md0 131072 1 writethrough default 0'
> 
> 41943040 - This is 20G, you should use the size of /dev/md0 in sectors
> 
> Also I think your block size is way too big, try 2048 rather tha 131072.
> 
> > BTW, for dm-cache is it support plug-and-play?
> 
> No idea what you mean.

I suspect the poster's asking if dmcaches will automatically reassemble
themselves.

I've been wondering myself what's the status of the lvm-tools integration? :)

--D
> 
> - Joe
> 
> --
> dm-devel mailing list
> dm-devel@redhat.com
> https://www.redhat.com/mailman/listinfo/dm-devel

^ permalink raw reply	[flat|nested] 6+ messages in thread
* Re: How to use dm-cache-target?
  2013-03-11 17:04   ` Darrick J. Wong
@ 2013-03-11 17:11     ` Zdenek Kabelac
  2013-03-12 13:27     ` thornber
  1 sibling, 0 replies; 6+ messages in thread
From: Zdenek Kabelac @ 2013-03-11 17:11 UTC (permalink / raw)
  To: dm-devel

Dne 11.3.2013 18:04, Darrick J. Wong napsal(a):
> On Mon, Mar 11, 2013 at 10:31:53AM +0000, thornber@redhat.com wrote:
>> On Mon, Mar 11, 2013 at 10:28:07AM +0800, majianpeng wrote:
>>> Hi all,
>>>      I am trying to use dm-cache-target on raid5.But i met a question.
>>>
>>>   Supposed: /dev/sdb1(5GB) is metadata; /dev/sdb2(20GB) is cache;/dev/md0 is raid5.
>>>
>>> 1:sutup my_cache
>>> dmsetup create my_cache --table '0 41943040 cache /dev/sdb1 /dev/sdb2 /dev/md0 131072 1 writethrough default 0'
>>
>> 41943040 - This is 20G, you should use the size of /dev/md0 in sectors
>>
>> Also I think your block size is way too big, try 2048 rather tha 131072.
>>
>>> BTW, for dm-cache is it support plug-and-play?
>>
>> No idea what you mean.
>
> I suspect the poster's asking if dmcaches will automatically reassemble
> themselves.
>
> I've been wondering myself what's the status of the lvm-tools integration? :)
>

On-going - will be integrated within some months.

Zdenek

^ permalink raw reply	[flat|nested] 6+ messages in thread
* Re: How to use dm-cache-target?
  2013-03-11 17:04   ` Darrick J. Wong
  2013-03-11 17:11     ` Zdenek Kabelac
@ 2013-03-12 13:27     ` thornber
  2013-03-12 16:56       ` Darrick J. Wong
  1 sibling, 1 reply; 6+ messages in thread
From: thornber @ 2013-03-12 13:27 UTC (permalink / raw)
  To: device-mapper development

On Mon, Mar 11, 2013 at 10:04:17AM -0700, Darrick J. Wong wrote:
> On Mon, Mar 11, 2013 at 10:31:53AM +0000, thornber@redhat.com wrote:
> I suspect the poster's asking if dmcaches will automatically reassemble
> themselves.
> 
> I've been wondering myself what's the status of the lvm-tools integration? :)

LVM changes at a glacial pace.  Would it be helpful if I knocked up
some tools to make it easier for people to play with this stuff?

- Joe

^ permalink raw reply	[flat|nested] 6+ messages in thread
* Re: How to use dm-cache-target?
  2013-03-12 13:27     ` thornber
@ 2013-03-12 16:56       ` Darrick J. Wong
  0 siblings, 0 replies; 6+ messages in thread
From: Darrick J. Wong @ 2013-03-12 16:56 UTC (permalink / raw)
  To: device-mapper development

On Tue, Mar 12, 2013 at 01:27:56PM +0000, thornber@redhat.com wrote:
> On Mon, Mar 11, 2013 at 10:04:17AM -0700, Darrick J. Wong wrote:
> > On Mon, Mar 11, 2013 at 10:31:53AM +0000, thornber@redhat.com wrote:
> > I suspect the poster's asking if dmcaches will automatically reassemble
> > themselves.
> > 
> > I've been wondering myself what's the status of the lvm-tools integration? :)
> 
> LVM changes at a glacial pace.  Would it be helpful if I knocked up
> some tools to make it easier for people to play with this stuff?

Well, we could possibly compare notes; here are some scripts that I've been
using:
http://djwong.org/docs/dmcache-tools.tar.gz

dm-format-blockdev and dm-load-cache are the key ones.  It also comes with udev
rules to (I hope) make the cache win any /dev symlink wars, and automount the
cache when all component devices are found.  They work for me, but beware they
might reflash your BIOS with rude poetry also. :)

--D
> 
> - Joe
> 
> --
> dm-devel mailing list
> dm-devel@redhat.com
> https://www.redhat.com/mailman/listinfo/dm-devel

^ permalink raw reply	[flat|nested] 6+ messages in thread
end of thread, other threads:[~2013-03-12 16:56 UTC | newest]

Thread overview: 6+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2013-03-11  2:28 How to use dm-cache-target? majianpeng
2013-03-11 10:31 ` thornber
2013-03-11 17:04   ` Darrick J. Wong
2013-03-11 17:11     ` Zdenek Kabelac
2013-03-12 13:27     ` thornber
2013-03-12 16:56       ` Darrick J. Wong

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