Re: [Moosefs-users] Some Research Questions about MooseFS

[Ken <ken...@gm...>]

Maybe I can TRY to answer sth.

On Tue, Sep 13, 2011 at 10:16 PM, Zachary Wagner <zw...@ha...>wrote:

> Hello,
> I am looking into MooseFS for one of my courses and I was hoping people
> could answer a few questions for me.
>
> Here are a few.  Some have sub-questions:
>
> 1. Does MooseFS save "deltas"?
> Does it save a whole copy of a changed document or just the changes? Does
> it have effects on the amount of data stored.
>
No, moose do not save changes set.


>
> 2. Does MooseFS synchronize all writes before returning?
>
> Yes. take a look at Write Proces in moosefs.org home page.


> 3. Does Master Server round robin the requests to different chunk servers?
> In deleting does Master or metalogger re-balance the distribution of data
> across chunkservers?
> What is the way the Master server assigns writes.
> Does Master server move data to alleviate congestion? Can system auto move
> chunks to spread reads out?
> How does master direct requests?
> What is the process of syncronizing data across chunks?
>
>> round robin
more detail:
for Write, the choosing is base on free space.
for Read, sort by ip address of all chunk server's and client's.

>> In deleting does Master or metalogger re-balance the distribution of data
across chunkservers?
I am not sure what this mean.
Master decide chunk put in witch chunk server.
Metalogger never *change* meta or filesystem.

>> What is the way the Master server assigns writes.
http://www.moosefs.org/system/html/write862-008171c7.png
a picture is worth than thound words.

>> Does Master server move data to alleviate congestion?
No

>> Can system auto move chunks to spread reads out?
i do not think so

>> What is the process of syncronizing data across chunks?
master send commands to chunk server. It's complex.

 .
>
> 4. System Specifications - what is most important?
> Processor - high GHz or high Cache memory?
> Fast Ram?
> Fast hard drive or big hard drive?
>
CPU and RAM is important to master.
Hard drive is important to chunk server.
Network transmission is important to the system.


>
> 5. Error Correction - Who is responsible for proper checksum?
> OS level or Checksum in meta logger?
>

There is a complex checksum task in chunk Server.
Chunk Server report the chunks which checksum failed


>
> Thank you for any help you can give me.
>
> Zach
>
>
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