Re: glusterfsd process thrashing CPU

["Adrian Kan" <adriankan@xxxxxxxxxx>]

Actually I had the same experience when I was using 3.4.2

https://www.mail-archive.com/gluster-users@xxxxxxxxxxx/msg15850.html

 

If I understand, I should be using FULL heal rather than DIFF for large vm-images?

 

I was not sure throttling was working for 3.4.2 or not.  I attempted to recover the entire volume filled with VM-images ranging from size 10G to 500G

I saw it was recovering 2 images at a time rather than all at once.

 

 

Thanks,

Adrian

 

 

 

 

 

From: gluster-users-bounces@xxxxxxxxxxx [mailto:gluster-users-bounces@xxxxxxxxxxx] On Behalf Of Pranith Kumar Karampuri
Sent: Tuesday, November 18, 2014 7:02 PM
To: Lindsay Mathieson; gluster-users
Subject: Re: glusterfsd process thrashing CPU

 

 

On 11/18/2014 04:14 PM, Lindsay Mathieson wrote:

On Tue, 18 Nov 2014 02:36:19 PM Pranith Kumar Karampuri wrote:

On 11/18/2014 01:17 PM, Lindsay Mathieson wrote:

On 18 November 2014 17:40, Pranith Kumar Karampuri <pkarampu@xxxxxxxxxx> 

wrote:

However given the files are tens of GB in size, won't it thrash my

network?

Yes you are right. I wonder why thrashing of the network is never

reported till now.

Not sure if you are being sarcastic or not :) But from what I've observed, 

sync operations seem to self throttle, I've not seen them use more than 50% of 

bandwidth, and given most setups have a dedicated network for the servers 

maybe they just don't notice if it takes a while?

No, I was not being sarcastic :-). I am genuinely wondering why it is not reported till now. May be Joe will have more inputs there, that is the reason I CCed him.

I still need to think about how best to solve this problem.

Setup a array of queues for self healing, sorted by size maybe?

Let me tell you a bit more about this issue:

there are two processes which heal the VM images:

1) self-heal-daemon. 2) Mount process.

Self-heal daemon heals one VM image at a time. But mount process

triggers self-heals for all the opened files(VM image is nothing but an

opened file from filesystem's perspective) when a brick goes down and

comes backup.

Thanks, interesting to know.

So we need to come up with a scheme to throttle self-heals

on the mount point to prevent this issue. I will update you as soon as I

come up with a fix. This should not be hard to do. Need some time to

choose the best approach. Thanks a lot for bringing up this issue.

Thanks you for looking at it!

Cheers,

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