Re: [Moosefs-users] Questions about MooseFS before putting it on the production env

[Michal B. <mic...@ge...>]

Hi Bob!

 

My replies are in the text. And for start please read this article:

http://www.moosefs.org/news-reader/items/metadata-ins-and-outs.html

 

 

From: ailms [mailto:ai...@qq...] 
Sent: Thursday, April 14, 2011 5:52 PM
To: moosefs-users
Subject: [Moosefs-users] Questions about MooseFS before putting it on the
production env

 

Dear guys,

We are plan to use moosefs as our store mechanism, which will be more than
5TB off-line command log. 

But now we have someconcern, Please find my queries below:

-----

1.  is there any plan about resolving the single-point failure of master ?

[MB] Please check a project developed by Thomas Hatch:
https://github.com/thatch45/mfs-failover 

It still needs some improvements but is a great way to test the failovers.
And Thomas needs some beta testers.

 

2.  The data will lost if master crash without dumping metadata from RAM
into disk,is it right?

[MB] Changelogs are saved continuously on the fly, there is very little
probability you would lose your data upon crash of the master server

 

3.  How can I know which data were lost if the question #2 happend?

[MB] When you make a recovery process of metadata you would know if it was
successful or not

 

4.  Dose the master only caches metadata read-only or will update the data
in RAM and flush to disk periodically?

[MB] The changes to metadata are saved to changelogs continuously on the fly

 

5.  Are the change logs based on the metadata.mfs.back or the data in RAM ?

[MB] We can consider them as based on RAM

 

6.  Can I change the default dumpling behaviour for master metadata from
per hour to user defined value? Such as 30 min?

[MB] As far as I remember, yes you can

 

7.  How can we make sure no data lost at any time with HA（KeepAlived）+
DRBD + mfs solution ?

[MB] We have not done such tests. Please first check a solution given in
question 1.

 

8.  The mfsmetaloggr didn't re-connect automatically even though I had
stoped and restarted the mfsmater, can only by manual?

[MB] Should have reconnected automatically. What was your environment? 

 

9.  which option in mfsmaster.cfg controls the rotation of changelog ?
according to the size ?  or each time when mfsmaster dump the metadata ?

[MB] Please see "man mfsmaster.cfg” - you should have all the options
listed

 

 

Kind regards

Michał Borychowski 

MooseFS Support Manager

_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

Gemius S.A.

ul. Wołoska 7, 02-672 Warszawa

Budynek MARS, klatka D

Tel.: +4822 874-41-00

Fax : +4822 874-41-01

 

 


Any help will be appreciated. Looking forward your answer.


Best Regard

Bob Lin