Re: [Moosefs-users] Write starvation

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

Hi Robert!

Parallel reading and writing to the same file indeed causes some write
delays. If it is not your case, adding 1-2 chunkservers and having a
dedicated machine for the master should help.


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

 

-----Original Message-----
From: Robert Sandilands [mailto:rsa...@ne...] 
Sent: Wednesday, June 29, 2011 4:30 AM
To: moo...@li...
Subject: [Moosefs-users] Write starvation

I have been moving data from existing non-distributed file systems onto 
a MooseFS file system.

I am using 1.6.20 on Centos 5.6.

While moving the data I have also transfered some of the normal 
read-only traffic load to use the data already moved onto the MFS volume.

What I can see is when there is any significant read traffic then write 
traffic slows down to a crawl.

When I look at the server charts for any of the chunk servers generated 
by mfscgiserv then it seems like read and write traffic seems to alternate.

Write traffic does not stop completely, but seems to slow down to < 10 
kB per second under high read traffic conditions. When the read traffic 
decreases the write traffic will increase to normal levels.

Is this a known problem? Is there something I can do to ensure that 
write traffic is not starved by read traffic?

Robert





----------------------------------------------------------------------------
--
All of the data generated in your IT infrastructure is seriously valuable.
Why? It contains a definitive record of application performance, security 
threats, fraudulent activity, and more. Splunk takes this data and makes 
sense of it. IT sense. And common sense.
http://p.sf.net/sfu/splunk-d2d-c2
_______________________________________________
moosefs-users mailing list
moo...@li...
https://lists.sourceforge.net/lists/listinfo/moosefs-users