From: Tomasz Chmielewski <mangoo@wpkg.org>
To: LVM general discussion and development <linux-lvm@redhat.com>
Cc: dm-devel@redhat.com
Subject: Re: Re: [RFC] Multiple Snapshots - Manageability problem
Date: Thu, 24 Jan 2008 12:02:52 +0100 [thread overview]
Message-ID: <4798705C.4080802@wpkg.org> (raw)
In-Reply-To: <a71bd89a0801231436k3653acfw9bd0a63f027daacf@mail.gmail.com>
Dan Kegel schrieb:
> On Jan 23, 2008 8:16 AM, Tomasz Chmielewski <mangoo@wpkg.org> wrote:
>> Vijai Babu Madhavan, Thu, 11 Jan 2007 11:18:13 -0700, wrote:
>>
>>> The problem of DM snapshots with multiple snapshots have been discussed
>>> in the lists quiet a bit (Most recently @
>>> https://www.redhat.com/archives/dm-devel/2006-October/msg00034.html).
>>>
>>> We are currently in the process of building a DM snapshot target that scales
>>> well with many snapshots (so that the changed blocks don't get copied to each
>>> snapshot). In this process, I would also like to validate an assumption.
>> Any news on that?
>>
>> Still, with multiple snapshots write performance degrades linearly - is
>> any work done to change that anytime soon?
>
> Yes. Dan Phillips has implemented a shared snapshot exception store.
> You can try it out now if you like; it's at http://zumastor.org.
> It feels a bit different from the user's point of view than LVM, though.
> It plays well with the device mapper and can be used with any
> block device (LVM or non-LVM).
Does it use device mapper (or it just "plays well with the device
mapper")? Or is it a totally different technology?
I didn't find it explained very clearly in Zumastor HOWTO on
http://zumastor.googlecode.com/svn/trunk/doc/zumastor-howto.html (other
than pointers to /dev/mapper/zumatest, which probably means it uses
device mapper).
--
Tomasz Chmielewski
http://wpkg.org
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WARNING: multiple messages have this Message-ID (diff)
From: Tomasz Chmielewski <mangoo@wpkg.org>
To: LVM general discussion and development <linux-lvm@redhat.com>
Cc: dm-devel@redhat.com
Subject: Re: [linux-lvm] Re: [RFC] Multiple Snapshots - Manageability problem
Date: Thu, 24 Jan 2008 12:02:52 +0100 [thread overview]
Message-ID: <4798705C.4080802@wpkg.org> (raw)
In-Reply-To: <a71bd89a0801231436k3653acfw9bd0a63f027daacf@mail.gmail.com>
Dan Kegel schrieb:
> On Jan 23, 2008 8:16 AM, Tomasz Chmielewski <mangoo@wpkg.org> wrote:
>> Vijai Babu Madhavan, Thu, 11 Jan 2007 11:18:13 -0700, wrote:
>>
>>> The problem of DM snapshots with multiple snapshots have been discussed
>>> in the lists quiet a bit (Most recently @
>>> https://www.redhat.com/archives/dm-devel/2006-October/msg00034.html).
>>>
>>> We are currently in the process of building a DM snapshot target that scales
>>> well with many snapshots (so that the changed blocks don't get copied to each
>>> snapshot). In this process, I would also like to validate an assumption.
>> Any news on that?
>>
>> Still, with multiple snapshots write performance degrades linearly - is
>> any work done to change that anytime soon?
>
> Yes. Dan Phillips has implemented a shared snapshot exception store.
> You can try it out now if you like; it's at http://zumastor.org.
> It feels a bit different from the user's point of view than LVM, though.
> It plays well with the device mapper and can be used with any
> block device (LVM or non-LVM).
Does it use device mapper (or it just "plays well with the device
mapper")? Or is it a totally different technology?
I didn't find it explained very clearly in Zumastor HOWTO on
http://zumastor.googlecode.com/svn/trunk/doc/zumastor-howto.html (other
than pointers to /dev/mapper/zumatest, which probably means it uses
device mapper).
--
Tomasz Chmielewski
http://wpkg.org
next prev parent reply other threads:[~2008-01-24 11:02 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-01-23 16:16 [RFC] Multiple Snapshots - Manageability problem Tomasz Chmielewski
2008-01-23 16:16 ` [linux-lvm] " Tomasz Chmielewski
2008-01-23 22:36 ` Dan Kegel
2008-01-23 22:36 ` [linux-lvm] " Dan Kegel
2008-01-24 11:02 ` Tomasz Chmielewski [this message]
2008-01-24 11:02 ` Tomasz Chmielewski
2008-01-24 13:18 ` Dan Kegel
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