Re: [MooseFS-Users] Slow replication between internal disks of 1 chunkserver

[Aleksander W. <ale...@mo...>]

Hi.
Yes.

Of course every thing depend on your system characteristic but if you
have a lot of replications, other operations can be starved by internal
chunkserver rebalancing process.
Hold to the view that one chunkserver will be overloaded by internal
replication process, whole cluster will have less number of I/O operations.

We recommend using default settings for HDD_REBALANCE_UTILIZATION option.

Best regards
Aleksander Wieliczko
Technical Support Engineer
MooseFS.com <moosefs.com>

On 04/03/2015 10:39 AM, Neddy, NH. Nam wrote:
> I increased HDD_REBALANCE_UTILIZATION value and the performance is
> improved significantly. So, is there any drawback if this value is too
> high?
>
> Thanks,
>
> On Fri, Apr 3, 2015 at 3:16 PM, Aleksander Wieliczko
> <ale...@mo...> wrote:
>> Hello.
>>
>> Starting from version MooseFS 2.0.x there's a new mechanism for internal
>> replication within chunkserver that can be controlled using
>> HDD_REBALANCE_UTILIZATION parameter in mfschunkserver.cfg file.
>>
>> So you have two options:
>> 1. You can set it to minimal value of 1, to decrease the impact of internal
>> rebalancing on i/o performance of the chunkserver.
>> HDD_REBALANCE_UTILIZATION = 1
>>
>> 2. You can set it to higher number during off-peak hours so the rebalancing
>> between chunkservers disks will finish faster in some maintenance window.
>>
>> Best regards
>> Aleksander Wieliczko
>> Technical Support Engineer
>> MooseFS.com
>>
>>
>> On 04/03/2015 09:45 AM, Davies Liu wrote:
>>
>> You can have a script to copy some files into new disk and create a
>> symlink for copied files.
>>
>> Once the disks got balanced, you can stop the chunk server, REMOVE all
>> symlinks, then start chunk server.
>>
>> On Thu, Apr 2, 2015 at 11:30 PM, Neddy, NH. Nam <na...@nd...> wrote:
>>
>> Hi,
>>
>> One disk was added to a chunkserver (2.0.60 CE) recently, but the
>> performance seems to be not good compared to adding totally new
>> chunkserver.
>>
>> All the disks are the same capacity but different brands. The
>> previously new added chunkserver has performed at limit write speed of
>> SATA2 (avg 60 MB/s), but the current server with brand disk added that
>> only has been wrting avg. 25 MB/s. (as seen in server graphs)
>>
>> Does anybody have idea on this?
>> Thanks,
>> ~Neddy
>>
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