Re: [MooseFS-Users] Minimum setup, local servers, remove VM as a master

[Remolina, D. J <dij...@ae...>]

Hi Nicolas,


I assume you are trying 3.x


You may want to also run the metalogger process on the second chunk server. You can then manually convert that server to a master if your master goes down since you are using it as a metalogger. On MooseFS 3.x *Pro* (paid version), you get multiple masters and HA is easily achieve by a multiple entry DNS A record.


Do note, that MooseFS 4.x is closed to being released and it will have the multiple master feature in the free community version, so you no longer have to pay to get the multiple master feature.


MooseFS requires the master to work, if the master is down and there are no other metadata masters available or you do not promote a metalogger to master, then your filesystem will not work.


Some tips on masters, you can run them on a separate machine, you need good amounts of RAM (look at docs in website for exact formulas) and since it is a single threaded process, you want the fastest cores you can get, not necessarily the most number of cores for your metadata server.


https://moosefs.com/support/#documentation



HTH,


Diego

________________________________
From: Nicolas Embriz <nb...@te...>
Sent: Saturday, June 16, 2018 6:32:45 AM
To: moo...@li...
Subject: [MooseFS-Users] Minimum setup, local servers, remove VM as a master

Hi, I am testing Moosefs on FreeBSD 11 so far using only 2 instances one behaving like master and chunkserver and other only as a chunkserver, so far all pretty good but while testing I notice that if the master goes down all the chunks become unresponsive, In my try to make a more redundant setup I am thinking of using a tiny VM (1GB ram 20GB disk) only to keep the master up and allow the 2 chunks to be operable, but I have some doubts.

If I understand properly the metadata is stored in the master and the chunckservers just store the raw data, therefore the master doesn’t need to be huge in storage as the chunservers , also when writing to data on one chunk server, only the metadata is sent to the master and the raw data is synced only between the chunks, and if I am understanding correctly the more intense use of network/bandwidth is between chunks and not the master, is this correct?  ( thinking on this to have a basic setup in where I could have 2 in home servers in the same network, but only the master in a remote tiny VM "always online" )

Now regarding the master, if it is down, I can’t access /read the files in the chunkservers, is there a way to configure the chunkservers to work in an online mode or being available to continue using what they have to until the master comes back and then just re-sync.

regards.