snapshot-removal - timeline ?

snapshot-removal - timeline ?

[Roland]

Hello,

is there a timeline for snapshot-removal ?

i did intensively play with btrfs about a year ago and was really impressed, 
but i quit due to the lack of snapshot removal.
(i tried btrfs mostly because of the snapshot feature)

has there been some progress on this or is there a timeline when this 
feature will be available ?

i wonder if it`s just so hard to implement or if it`s  just too low priority 
on the todo list..... maybe both ? ;)

regards
roland

Re: snapshot-removal - timeline ?

[Chris Mason]

On Sat, Aug 01, 2009 at 02:03:37PM +0200, Roland wrote:
> Hello,
> 
> is there a timeline for snapshot-removal ?
> 
> i did intensively play with btrfs about a year ago and was really
> impressed, but i quit due to the lack of snapshot removal.
> (i tried btrfs mostly because of the snapshot feature)
> 
> has there been some progress on this or is there a timeline when
> this feature will be available ?
> 
> i wonder if it`s just so hard to implement or if it`s  just too low
> priority on the todo list..... maybe both ? ;)

Its a little of both ;)  The plan is to have this in 2.6.32

-chris

Re: snapshot-removal - timeline ?

[Roy Sigurd Karlsbakk]

On 3. aug.. 2009, at 15.04, Chris Mason wrote:

> On Sat, Aug 01, 2009 at 02:03:37PM +0200, Roland wrote:
>> Hello,
>>
>> is there a timeline for snapshot-removal ?
>>
>> i did intensively play with btrfs about a year ago and was really
>> impressed, but i quit due to the lack of snapshot removal.
>> (i tried btrfs mostly because of the snapshot feature)
>>
>> has there been some progress on this or is there a timeline when
>> this feature will be available ?
>>
>> i wonder if it`s just so hard to implement or if it`s  just too low
>> priority on the todo list..... maybe both ? ;)
>
> Its a little of both ;)  The plan is to have this in 2.6.32


Last I heard, someone was saying .31... Is it being moved?
--
Roy Sigurd Karlsbakk
(+47) 97542685
roy@karlsbakk.net
http://blogg.karlsbakk.net/
--
I all pedagogikk er det essensielt at pensum presenteres =20
intelligibelt. Det er et element=E6rt imperativ for alle pedagoger =E5 =
=20
unng=E5 eksessiv anvendelse av idiomer med fremmed opprinnelse. I de =20
fleste tilfeller eksisterer adekvate og relevante synonymer p=E5 norsk.

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Re: snapshot-removal - timeline ?

[Chris Mason]

On Mon, Aug 03, 2009 at 04:33:13PM +0200, Roy Sigurd Karlsbakk wrote:
> On 3. aug.. 2009, at 15.04, Chris Mason wrote:
> 
> >On Sat, Aug 01, 2009 at 02:03:37PM +0200, Roland wrote:
> >>Hello,
> >>
> >>is there a timeline for snapshot-removal ?
> >>
> >>i did intensively play with btrfs about a year ago and was really
> >>impressed, but i quit due to the lack of snapshot removal.
> >>(i tried btrfs mostly because of the snapshot feature)
> >>
> >>has there been some progress on this or is there a timeline when
> >>this feature will be available ?
> >>
> >>i wonder if it`s just so hard to implement or if it`s  just too low
> >>priority on the todo list..... maybe both ? ;)
> >
> >Its a little of both ;)  The plan is to have this in 2.6.32
> 
> 
> Last I heard, someone was saying .31... Is it being moved?

Yes, it was delayed so we could finalize the other changes in .31.

-chris

Re: snapshot-removal - timeline ?

[Roy Sigurd Karlsbakk]

On 3. aug.. 2009, at 18.18, Chris Mason wrote:
> On Mon, Aug 03, 2009 at 04:33:13PM +0200, Roy Sigurd Karlsbakk wrote:
>> On 3. aug.. 2009, at 15.04, Chris Mason wrote:
>>
>>> On Sat, Aug 01, 2009 at 02:03:37PM +0200, Roland wrote:
>>>> Hello,
>>>>
>>>> is there a timeline for snapshot-removal ?
>>>>
>>>> i did intensively play with btrfs about a year ago and was really
>>>> impressed, but i quit due to the lack of snapshot removal.
>>>> (i tried btrfs mostly because of the snapshot feature)
>>>>
>>>> has there been some progress on this or is there a timeline when
>>>> this feature will be available ?
>>>>
>>>> i wonder if it`s just so hard to implement or if it`s  just too lo=
w
>>>> priority on the todo list..... maybe both ? ;)
>>>
>>> Its a little of both ;)  The plan is to have this in 2.6.32
>>
>>
>> Last I heard, someone was saying .31... Is it being moved?
>
> Yes, it was delayed so we could finalize the other changes in .31.


It's strange that such a small thing should be delayed so much. If =20
snapshot removal was working, I'm quite sure we might get more users =20
and thereby more stable code faster.

roy
--
Roy Sigurd Karlsbakk
(+47) 97542685
roy@karlsbakk.net
http://blogg.karlsbakk.net/
--
I all pedagogikk er det essensielt at pensum presenteres =20
intelligibelt. Det er et element=E6rt imperativ for alle pedagoger =E5 =
=20
unng=E5 eksessiv anvendelse av idiomer med fremmed opprinnelse. I de =20
fleste tilfeller eksisterer adekvate og relevante synonymer p=E5 norsk.

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Re: snapshot-removal - timeline ?

[Brian Neu]

> >>>> Hello,
> >>>>
> >>>> is there a timeline for snapshot-removal
> ?
> >>>>
> >>>> i did intensively play with btrfs about a
> year ago and was really
> >>>> impressed, but i quit due to the lack of
> snapshot removal.
> >>>> (i tried btrfs mostly because of the
> snapshot feature)
> >>>>
> >>>> has there been some progress on this or is
> there a timeline when
> >>>> this feature will be available ?
> >>>>
> >>>> i wonder if it`s just so hard to implement
> or if it`s  just too low
> >>>> priority on the todo list..... maybe both
> ? ;)
> >>>
> >>> Its a little of both ;)  The plan is to
> have this in 2.6.32
> >>
> >>
> >> Last I heard, someone was saying .31... Is it
> being moved?
> >
> > Yes, it was delayed so we could finalize the other
> changes in .31.
>
>
> It's strange that such a small thing should be delayed so
> much. If snapshot removal was working, I'm quite sure we
> might get more users and thereby more stable code faster.
>
> roy
> --


I don't know whether it's small in required effort, but I know as a user the feature would be big.  I actually have a non-critical, redundant backup system that I was set to install with .31, betting on the snapshot removal.  You can't please all the people all the time, but I thought I'd write to voice an opinion for prioritizing it for .32.  Thanks.

Re: snapshot-removal - timeline ?

[Chris Mason]

On Tue, Aug 04, 2009 at 09:52:51AM +0200, Roy Sigurd Karlsbakk wrote:
> On 3. aug.. 2009, at 18.18, Chris Mason wrote:
> >On Mon, Aug 03, 2009 at 04:33:13PM +0200, Roy Sigurd Karlsbakk wrote:
> >>On 3. aug.. 2009, at 15.04, Chris Mason wrote:
> >>
> >>>On Sat, Aug 01, 2009 at 02:03:37PM +0200, Roland wrote:
> >>>>Hello,
> >>>>
> >>>>is there a timeline for snapshot-removal ?
> >>>>
> >>>>i did intensively play with btrfs about a year ago and was really
> >>>>impressed, but i quit due to the lack of snapshot removal.
> >>>>(i tried btrfs mostly because of the snapshot feature)
> >>>>
> >>>>has there been some progress on this or is there a timeline when
> >>>>this feature will be available ?
> >>>>
> >>>>i wonder if it`s just so hard to implement or if it`s  just too low
> >>>>priority on the todo list..... maybe both ? ;)
> >>>
> >>>Its a little of both ;)  The plan is to have this in 2.6.32
> >>
> >>
> >>Last I heard, someone was saying .31... Is it being moved?
> >
> >Yes, it was delayed so we could finalize the other changes in .31.
> 
> 
> It's strange that such a small thing should be delayed so much. If
> snapshot removal was working, I'm quite sure we might get more users
> and thereby more stable code faster.

It's a small feature but it gets deep into the difficult parts of the
dentry cache to do it right.  So, it definitely isn't easy.

-chris

Re: snapshot-removal - timeline ?

[Roy Sigurd Karlsbakk]

On 4. aug.. 2009, at 20.33, Chris Mason wrote:

>> It's strange that such a small thing should be delayed so much. If
>> snapshot removal was working, I'm quite sure we might get more users
>> and thereby more stable code faster.
>
> It's a small feature but it gets deep into the difficult parts of the
> dentry cache to do it right.  So, it definitely isn't easy.


I'd say it's a pretty elemetary feature to be able to remove something =
=20
you have created. I know, you can remove the files and so on, but =20
still, having a bunch of old and empty snapshots lying around is no =20
good.

roy
--
Roy Sigurd Karlsbakk
(+47) 97542685
roy@karlsbakk.net
http://blogg.karlsbakk.net/
--
I all pedagogikk er det essensielt at pensum presenteres =20
intelligibelt. Det er et element=E6rt imperativ for alle pedagoger =E5 =
=20
unng=E5 eksessiv anvendelse av idiomer med fremmed opprinnelse. I de =20
fleste tilfeller eksisterer adekvate og relevante synonymer p=E5 norsk.

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Re: snapshot-removal - timeline ?

[Josef Bacik]

On Wed, Aug 05, 2009 at 01:18:33PM +0200, Roy Sigurd Karlsbakk wrote:
> On 4. aug.. 2009, at 20.33, Chris Mason wrote:
>
>>> It's strange that such a small thing should be delayed so much. If
>>> snapshot removal was working, I'm quite sure we might get more users
>>> and thereby more stable code faster.
>>
>> It's a small feature but it gets deep into the difficult parts of the
>> dentry cache to do it right.  So, it definitely isn't easy.
>
>
> I'd say it's a pretty elemetary feature to be able to remove something  
> you have created. I know, you can remove the files and so on, but still, 
> having a bunch of old and empty snapshots lying around is no good.
>

Patches are always welcome.

Josef

Re: snapshot-removal - timeline ?

[Andrey Kuzmin]

On Wed, Aug 5, 2009 at 3:18 PM, Roy Sigurd Karlsbakk <roy@karlsbakk.net=
> wrote:
>
> On 4. aug.. 2009, at 20.33, Chris Mason wrote:
>
>>> It's strange that such a small thing should be delayed so much. If
>>> snapshot removal was working, I'm quite sure we might get more user=
s
>>> and thereby more stable code faster.
>>
>> It's a small feature but it gets deep into the difficult parts of th=
e
>> dentry cache to do it right. =A0So, it definitely isn't easy.
>
>
> I'd say it's a pretty elemetary feature to be able to remove somethin=
g you have created.

Snapshots are somewhat counter-intuitive in many respects: for
instance, one snapshot-capable file-system performs writes to  a
dataset with snapshots _faster_ than to the same dataset w/o
snapshots. Snapshot removal is no exception - it's a bit more complex
than one would think.

Regards,
Andrey

> I know, you can remove the files and so on, but still, having a bunch=
 of old and empty
> snapshots lying around is no good.


>
> roy
> --
> Roy Sigurd Karlsbakk
> (+47) 97542685
> roy@karlsbakk.net
> http://blogg.karlsbakk.net/
> --
> I all pedagogikk er det essensielt at pensum presenteres intelligibel=
t. Det er et element=E6rt imperativ for alle pedagoger =E5 unng=E5 ekse=
ssiv anvendelse av idiomer med fremmed opprinnelse. I de fleste tilfell=
er eksisterer adekvate og relevante synonymer p=E5 norsk.
>
> --
> To unsubscribe from this list: send the line "unsubscribe linux-btrfs=
" in
> the body of a message to majordomo@vger.kernel.org
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Re: snapshot-removal - timeline ?

[Christian Mikovits]

I guess whats really hard to program: snapshot removal when not
copying the data, but only pointing to that data and writing the
differences from that point on. Figure out how difficult it is to
remove snapshot 3 of 7; When snapshot 1 is the original data, snap2
the diff from 1 to 2, snap 3 the diff from 2 to 3, .... so you have to
merge the data of snap 3 and 4.

But the benefits are obvious: instant snapshots and very low space
consumption (in case you don't delete lots of your 'live' data).

On 8/5/09, Andrey Kuzmin <andrey.v.kuzmin@gmail.com> wrote:
> On Wed, Aug 5, 2009 at 3:18 PM, Roy Sigurd Karlsbakk <roy@karlsbakk.n=
et>
> wrote:
>>
>> On 4. aug.. 2009, at 20.33, Chris Mason wrote:
>>
>>>> It's strange that such a small thing should be delayed so much. If
>>>> snapshot removal was working, I'm quite sure we might get more use=
rs
>>>> and thereby more stable code faster.
>>>
>>> It's a small feature but it gets deep into the difficult parts of t=
he
>>> dentry cache to do it right. =C2=A0So, it definitely isn't easy.
>>
>>
>> I'd say it's a pretty elemetary feature to be able to remove somethi=
ng you
>> have created.
>
> Snapshots are somewhat counter-intuitive in many respects: for
> instance, one snapshot-capable file-system performs writes to  a
> dataset with snapshots _faster_ than to the same dataset w/o
> snapshots. Snapshot removal is no exception - it's a bit more complex
> than one would think.
>
> Regards,
> Andrey
>
>> I know, you can remove the files and so on, but still, having a bunc=
h of
>> old and empty
>> snapshots lying around is no good.
>
>
>>
>> roy
>> --
>> Roy Sigurd Karlsbakk
>> (+47) 97542685
>> roy@karlsbakk.net
>> http://blogg.karlsbakk.net/
>> --
>> I all pedagogikk er det essensielt at pensum presenteres intelligibe=
lt.
>> Det er et element=C3=A6rt imperativ for alle pedagoger =C3=A5 unng=C3=
=A5 eksessiv
>> anvendelse av idiomer med fremmed opprinnelse. I de fleste tilfeller
>> eksisterer adekvate og relevante synonymer p=C3=A5 norsk.
>>
>> --
>> To unsubscribe from this list: send the line "unsubscribe linux-btrf=
s" in
>> the body of a message to majordomo@vger.kernel.org
>> More majordomo info at =C2=A0http://vger.kernel.org/majordomo-info.h=
tml
> --
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Re: snapshot-removal - timeline ?

[Andrey Kuzmin]

On Wed, Aug 5, 2009 at 10:46 PM, Christian Mikovits<gaelic@luchmhor.net=
> wrote:
> I guess whats really hard to program: snapshot removal when not
> copying the data, but only pointing to that data and writing the
> differences from that point on. Figure out how difficult it is to
> remove snapshot 3 of 7; When snapshot 1 is the original data, snap2
> the diff from 1 to 2, snap 3 the diff from 2 to 3, .... so you have t=
o
> merge the data of snap 3 and 4.

Depends on the snapshot design: if snapshots are implemented with
reference counts, nothing needs to be merged (but simplicity in this
respect comes at the cost of garbage collection).

Regards,
Andrey

>
> But the benefits are obvious: instant snapshots and very low space
> consumption (in case you don't delete lots of your 'live' data).
>
> On 8/5/09, Andrey Kuzmin <andrey.v.kuzmin@gmail.com> wrote:
>> On Wed, Aug 5, 2009 at 3:18 PM, Roy Sigurd Karlsbakk <roy@karlsbakk.=
net>
>> wrote:
>>>
>>> On 4. aug.. 2009, at 20.33, Chris Mason wrote:
>>>
>>>>> It's strange that such a small thing should be delayed so much. I=
f
>>>>> snapshot removal was working, I'm quite sure we might get more us=
ers
>>>>> and thereby more stable code faster.
>>>>
>>>> It's a small feature but it gets deep into the difficult parts of =
the
>>>> dentry cache to do it right. =A0So, it definitely isn't easy.
>>>
>>>
>>> I'd say it's a pretty elemetary feature to be able to remove someth=
ing you
>>> have created.
>>
>> Snapshots are somewhat counter-intuitive in many respects: for
>> instance, one snapshot-capable file-system performs writes to =A0a
>> dataset with snapshots _faster_ than to the same dataset w/o
>> snapshots. Snapshot removal is no exception - it's a bit more comple=
x
>> than one would think.
>>
>> Regards,
>> Andrey
>>
>>> I know, you can remove the files and so on, but still, having a bun=
ch of
>>> old and empty
>>> snapshots lying around is no good.
>>
>>
>>>
>>> roy
>>> --
>>> Roy Sigurd Karlsbakk
>>> (+47) 97542685
>>> roy@karlsbakk.net
>>> http://blogg.karlsbakk.net/
>>> --
>>> I all pedagogikk er det essensielt at pensum presenteres intelligib=
elt.
>>> Det er et element=E6rt imperativ for alle pedagoger =E5 unng=E5 eks=
essiv
>>> anvendelse av idiomer med fremmed opprinnelse. I de fleste tilfelle=
r
>>> eksisterer adekvate og relevante synonymer p=E5 norsk.
>>>
>>> --
>>> To unsubscribe from this list: send the line "unsubscribe linux-btr=
fs" in
>>> the body of a message to majordomo@vger.kernel.org
>>> More majordomo info at =A0http://vger.kernel.org/majordomo-info.htm=
l
>> --
>> To unsubscribe from this list: send the line "unsubscribe linux-btrf=
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>> the body of a message to majordomo@vger.kernel.org
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>>
>
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