* Default low water mark threshold for a new thin pool
@ 2013-02-05 9:00 ` M. Mohan Kumar
0 siblings, 0 replies; 6+ messages in thread
From: M. Mohan Kumar @ 2013-02-05 9:00 UTC (permalink / raw)
To: dm-devel, lvm-devel
Hello,
We are adding a lvm2api for creating a thin pool. During thin pool
creation if user does not specify anything for the low water mark
thresold, it would result in 0 and no events will be generated when thin
pool capacity is reaching its full size. IMHO, if user does not specify
anything during thin pool creation, we can assume some value something
like 25%, so that when a thin pool is consumed more than 75%, there will
be an event generated for that pool.
I am not sure what should be the default low water threshold
percentage. Is there any recommended value for low water threshold value
in dm thin pools?
Regards,
M. Mohan Kumar
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^ permalink raw reply [flat|nested] 6+ messages in thread
* Default low water mark threshold for a new thin pool
@ 2013-02-05 9:00 ` M. Mohan Kumar
0 siblings, 0 replies; 6+ messages in thread
From: M. Mohan Kumar @ 2013-02-05 9:00 UTC (permalink / raw)
To: lvm-devel
Hello,
We are adding a lvm2api for creating a thin pool. During thin pool
creation if user does not specify anything for the low water mark
thresold, it would result in 0 and no events will be generated when thin
pool capacity is reaching its full size. IMHO, if user does not specify
anything during thin pool creation, we can assume some value something
like 25%, so that when a thin pool is consumed more than 75%, there will
be an event generated for that pool.
I am not sure what should be the default low water threshold
percentage. Is there any recommended value for low water threshold value
in dm thin pools?
Regards,
M. Mohan Kumar
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: Default low water mark threshold for a new thin pool
2013-02-05 9:00 ` M. Mohan Kumar
@ 2013-02-05 12:18 ` thornber
-1 siblings, 0 replies; 6+ messages in thread
From: thornber @ 2013-02-05 12:18 UTC (permalink / raw)
To: LVM2 development; +Cc: dm-devel
On Tue, Feb 05, 2013 at 02:30:00PM +0530, M. Mohan Kumar wrote:
>
> Hello,
>
> We are adding a lvm2api for creating a thin pool. During thin pool
> creation if user does not specify anything for the low water mark
> thresold, it would result in 0 and no events will be generated when thin
> pool capacity is reaching its full size.
An event will be generated.
> I am not sure what should be the default low water threshold
> percentage. Is there any recommended value for low water threshold value
> in dm thin pools?
It's very hard to say since it depends on your use case. In general
you want to allow dmeventd plenty of time to extend the pool before
you run out of space. So if you're seeing a _peak_ provisioning rate of
100meg a minute, I'd set the lwm to about 100meg. It would be nice if LVM
could help you through this process.
- Joe
--
lvm-devel mailing list
lvm-devel@redhat.com
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^ permalink raw reply [flat|nested] 6+ messages in thread
* Default low water mark threshold for a new thin pool
@ 2013-02-05 12:18 ` thornber
0 siblings, 0 replies; 6+ messages in thread
From: thornber @ 2013-02-05 12:18 UTC (permalink / raw)
To: lvm-devel
On Tue, Feb 05, 2013 at 02:30:00PM +0530, M. Mohan Kumar wrote:
>
> Hello,
>
> We are adding a lvm2api for creating a thin pool. During thin pool
> creation if user does not specify anything for the low water mark
> thresold, it would result in 0 and no events will be generated when thin
> pool capacity is reaching its full size.
An event will be generated.
> I am not sure what should be the default low water threshold
> percentage. Is there any recommended value for low water threshold value
> in dm thin pools?
It's very hard to say since it depends on your use case. In general
you want to allow dmeventd plenty of time to extend the pool before
you run out of space. So if you're seeing a _peak_ provisioning rate of
100meg a minute, I'd set the lwm to about 100meg. It would be nice if LVM
could help you through this process.
- Joe
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: Default low water mark threshold for a new thin pool
2013-02-05 12:18 ` thornber
@ 2013-02-05 16:56 ` M. Mohan Kumar
-1 siblings, 0 replies; 6+ messages in thread
From: M. Mohan Kumar @ 2013-02-05 16:56 UTC (permalink / raw)
To: thornber, LVM2 development; +Cc: dm-devel
thornber@redhat.com writes:
> On Tue, Feb 05, 2013 at 02:30:00PM +0530, M. Mohan Kumar wrote:
>>
>> Hello,
>>
>> We are adding a lvm2api for creating a thin pool. During thin pool
>> creation if user does not specify anything for the low water mark
>> thresold, it would result in 0 and no events will be generated when thin
>> pool capacity is reaching its full size.
>
> An event will be generated.
Yeah, I missed that. But if thin pool is consumed fully there is no
enough time to resize the pool and it may result in unwanted scenario?
>
>> I am not sure what should be the default low water threshold
>> percentage. Is there any recommended value for low water threshold value
>> in dm thin pools?
>
> It's very hard to say since it depends on your use case. In general
> you want to allow dmeventd plenty of time to extend the pool before
> you run out of space. So if you're seeing a _peak_ provisioning rate of
> 100meg a minute, I'd set the lwm to about 100meg. It would be nice if LVM
> could help you through this process.
Do you mean mesaure how much MB/blocks dm-thin is able to provision in a
minute and treat it as the default lwm blocks?
>
> - Joe
>
> --
> lvm-devel mailing list
> lvm-devel@redhat.com
> https://www.redhat.com/mailman/listinfo/lvm-devel
--
lvm-devel mailing list
lvm-devel@redhat.com
https://www.redhat.com/mailman/listinfo/lvm-devel
^ permalink raw reply [flat|nested] 6+ messages in thread
* Default low water mark threshold for a new thin pool
@ 2013-02-05 16:56 ` M. Mohan Kumar
0 siblings, 0 replies; 6+ messages in thread
From: M. Mohan Kumar @ 2013-02-05 16:56 UTC (permalink / raw)
To: lvm-devel
thornber at redhat.com writes:
> On Tue, Feb 05, 2013 at 02:30:00PM +0530, M. Mohan Kumar wrote:
>>
>> Hello,
>>
>> We are adding a lvm2api for creating a thin pool. During thin pool
>> creation if user does not specify anything for the low water mark
>> thresold, it would result in 0 and no events will be generated when thin
>> pool capacity is reaching its full size.
>
> An event will be generated.
Yeah, I missed that. But if thin pool is consumed fully there is no
enough time to resize the pool and it may result in unwanted scenario?
>
>> I am not sure what should be the default low water threshold
>> percentage. Is there any recommended value for low water threshold value
>> in dm thin pools?
>
> It's very hard to say since it depends on your use case. In general
> you want to allow dmeventd plenty of time to extend the pool before
> you run out of space. So if you're seeing a _peak_ provisioning rate of
> 100meg a minute, I'd set the lwm to about 100meg. It would be nice if LVM
> could help you through this process.
Do you mean mesaure how much MB/blocks dm-thin is able to provision in a
minute and treat it as the default lwm blocks?
>
> - Joe
>
> --
> lvm-devel mailing list
> lvm-devel at redhat.com
> https://www.redhat.com/mailman/listinfo/lvm-devel
^ permalink raw reply [flat|nested] 6+ messages in thread
end of thread, other threads:[~2013-02-05 16:56 UTC | newest]
Thread overview: 6+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2013-02-05 9:00 Default low water mark threshold for a new thin pool M. Mohan Kumar
2013-02-05 9:00 ` M. Mohan Kumar
2013-02-05 12:18 ` thornber
2013-02-05 12:18 ` thornber
2013-02-05 16:56 ` M. Mohan Kumar
2013-02-05 16:56 ` M. Mohan Kumar
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