Re: RAID on GLUSTER node

[Pranith Kumar Karampuri <pkarampu@xxxxxxxxxx>]

On 01/12/2016 01:26 PM, Pawan Devaiah wrote:

Thanks for your response Pranith and Mathieu,

Pranith: To answer your question, I am planning to use this storage for two main workloads.

1. As a shared storage for VMs.

EC as it is today is not good for this.

2. As a NFS Storage for files.

If the above is for storing archive data. EC is nice here.

Pranith

We are a online backup company so we store few hundred Terra bytes of data.

Mathieu: I appreciate your concern, however as a system admins sometimes we get paranoid and try to control everything under the Sun.

I know I can only control what I can.

Having said that, No, I have pair of servers to start with so at the moment I am just evaluating and preparing for proof of concept, after which I am going to propose to my management, if they are happy then we will proceed further.

Regards,

Dev

On Tue, Jan 12, 2016 at 7:30 PM, Mathieu Chateau <mathieu.chateau@xxxxxxx> wrote:

Hello,

For any system, 36 disks raise disk failure probability. Do you plan GlusterFS with only one server?

You should think about failure at each level and be prepared for it:

• Motherboard failure (full server down)
• Disks failure
• Network cable failure 
  
• File system corruption (time needed for fsck)
• File/folder removed by mistake (backup)

Using or not raid depend on your answer on these questions and performance needed. 

It also depend how "good" is raid controller in your server, like if it has battery and 1GB of cache.

When many disks are bought at same time (1 order, serial number close to each other), they may fail in near time to each other (if something bad happened in manufactory).

I already saw like 3 disks failing in few days.

just my 2 cents,

Cordialement,
Mathieu CHATEAU
http://www.lotp.fr

2016-01-12 4:36 GMT+01:00 Pranith Kumar Karampuri <pkarampu@xxxxxxxxxx>:

On 01/12/2016 04:34 AM, Pawan Devaiah wrote:

Hi All,

We have a fairly powerful server sitting at office with 128 Gig RAM and 36 X 4 TB drives. I am planning to utilize this server as a backend storage with GlusterFS on it.

I have been doing lot of reading on Glusterfs, but I do not see any definite recommendation on having RAID on GLUSTER nodes.

Is it recommended to have RAID on GLUSTER nodes specially for the bricks?

If Yes, is it not contrary to the latest Erasure code implemented in Gluster or is it still not ready for production environment?

I am happy to implement RAID but my two main concern are

1. I want to make most of the disk space available.

2. I am also concerned about the rebuild time after disk failure on the RAID.

What is the workload you have?

We found in our testing that random read/write workload with Erasure coded volumes is not as good as we get with replication. There are enhancements in progress at the moment to address these things which we are yet to merge and re-test.

Pranith

Thanks

Dev

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