Force to redistribute tablets among available tservers

[Maxim Kolchin <ko...@gmail.com>]

Hi all,

Imagine a cluster with one tserver which hosts N tablets. At some point, I
decide to add another tserver to the cluster. Is it possible force Accumulo
to move (redistribute) part of tablets to the new tserver? If it so, how to
do that? I tried to google and to look at the list of Accumulo shell
commands, but without any success.

Thank you in advance!
Maxim Kolchin

E-mail: kolchinmax@gmail.com
Homepage: http://kolchinmax.ru

Re: Force to redistribute tablets among available tservers

[Jeff Kubina <je...@gmail.com>]

Correct, the table can't be in use while taking it offline and then online.

The default balancer is called about every minute. You should be able to
see that in the master's logs.

It is certainly possible, but not easy, to adapt the default balancer
to redistribute
tablets more quickly.

-- 
Jeff Kubina
410-988-4436


On Thu, Jul 5, 2018 at 5:45 AM, Maxim Kolchin <ko...@gmail.com> wrote:

> Hi Jeff,
>
> > an individual table by taking it offline and then online
>
> Thank you! I'll try that. But it means that it's not possible to do while
> the table is being used, is it correct?
>
> Is it possible to somehow adapt the default balancer's behaviour, so that
> it would redistribute tablets after N secs (or mins) a new tserver being
> online?
>
> Maxim
>
> On Wed, Jul 4, 2018 at 5:05 PM Jeff Kubina <je...@gmail.com> wrote:
>
>> Maxim, I don't think there is a command to force that since the master's
>> default balancer will do that automatically for all the tablets. You can
>> speed the process up for an individual table by taking it offline and then
>> online; the table's tablets will be balanced across the tservers when it
>> comes back online.
>>
>> --
>> Jeff Kubina
>> 410-988-4436
>>
>>
>> On Wed, Jul 4, 2018 at 7:23 AM, Maxim Kolchin <ko...@gmail.com>
>> wrote:
>>
>>> Hi all,
>>>
>>> Imagine a cluster with one tserver which hosts N tablets. At some point,
>>> I decide to add another tserver to the cluster. Is it possible force
>>> Accumulo to move (redistribute) part of tablets to the new tserver? If it
>>> so, how to do that? I tried to google and to look at the list of Accumulo
>>> shell commands, but without any success.
>>>
>>> Thank you in advance!
>>> Maxim Kolchin
>>>
>>> E-mail: kolchinmax@gmail.com
>>> Homepage: http://kolchinmax.ru
>>>
>>
>>

Re: Force to redistribute tablets among available tservers

[Maxim Kolchin <ko...@gmail.com>]

Hi Jeff,

> an individual table by taking it offline and then online

Thank you! I'll try that. But it means that it's not possible to do while
the table is being used, is it correct?

Is it possible to somehow adapt the default balancer's behaviour, so that
it would redistribute tablets after N secs (or mins) a new tserver being
online?

Maxim

On Wed, Jul 4, 2018 at 5:05 PM Jeff Kubina <je...@gmail.com> wrote:

> Maxim, I don't think there is a command to force that since the master's
> default balancer will do that automatically for all the tablets. You can
> speed the process up for an individual table by taking it offline and then
> online; the table's tablets will be balanced across the tservers when it
> comes back online.
>
> --
> Jeff Kubina
> 410-988-4436
>
>
> On Wed, Jul 4, 2018 at 7:23 AM, Maxim Kolchin <ko...@gmail.com>
> wrote:
>
>> Hi all,
>>
>> Imagine a cluster with one tserver which hosts N tablets. At some point,
>> I decide to add another tserver to the cluster. Is it possible force
>> Accumulo to move (redistribute) part of tablets to the new tserver? If it
>> so, how to do that? I tried to google and to look at the list of Accumulo
>> shell commands, but without any success.
>>
>> Thank you in advance!
>> Maxim Kolchin
>>
>> E-mail: kolchinmax@gmail.com
>> Homepage: http://kolchinmax.ru
>>
>
>

Re: Force to redistribute tablets among available tservers

[Jeff Kubina <je...@gmail.com>]

Maxim, I don't think there is a command to force that since the master's
default balancer will do that automatically for all the tablets. You can
speed the process up for an individual table by taking it offline and then
online; the table's tablets will be balanced across the tservers when it
comes back online.

-- 
Jeff Kubina
410-988-4436


On Wed, Jul 4, 2018 at 7:23 AM, Maxim Kolchin <ko...@gmail.com> wrote:

> Hi all,
>
> Imagine a cluster with one tserver which hosts N tablets. At some point, I
> decide to add another tserver to the cluster. Is it possible force Accumulo
> to move (redistribute) part of tablets to the new tserver? If it so, how to
> do that? I tried to google and to look at the list of Accumulo shell
> commands, but without any success.
>
> Thank you in advance!
> Maxim Kolchin
>
> E-mail: kolchinmax@gmail.com
> Homepage: http://kolchinmax.ru
>