[DRBD-user] Optimizing for file copys over NFS?

Todd Denniston Todd.Denniston at ssa.crane.navy.mil
Wed Dec 17 16:11:54 CET 2008

Note: "permalinks" may not be as permanent as we would like,
direct links of old sources may well be a few messages off.


Mike Sweetser - Adhost wrote, On 12/23/-28158 02:59 PM:
> Hello,
> 
> We have a DRBD installation with the following configuration that we're
> experiencing serious performance issues with on the server when copying
> a large amount of files, or a large file:
> 

<SNIP>
I can't help with the DRBD portion of this, because I am running a really old 
version of DRBD, but if you search the news group there are several "need for 
speed" articles that have been written, they gives some hints for tuning DRBD 
for speed.  Also what hardware? 100Mb 1000Mb network, infinaban, Broadcom 
NICs, one, two or four NICs per machine, bonded?
have you tweaked the MTU on the drbd replication link yet?

you have the metadata device on the same physical device as the drbd data, 
which causes seek time slowdowns.

> 
> What can we do to optimize this?  It's used as an NFS drive for several
> web servers, so the faster it can go for this, the better.  Any help on
> optimizing DRBD would be appreciated.  Also, are there any helpful hints
> for using DRBD with NFS, as far as what parameters to use for the NFS
> mounts to speed things up?
> 
> Thank You,
> Mike Sweetser
> 

On the NFS front:
Make sure you have LOTS of ram (>2 GB) to cache the drives you are serving.

When mounting the drbd drives on the server, mount them noatime or relatime, 
if you are not running on a new enough kernel to always mount them relatime.

While the system is running, use top to see if most of the nfsd you have are 
running most of the time, i.e., should you mod the nfs startup script to start 
more nfsd?.

And never discount the nice guides at
http://www.drbd.org/
http://www.drbd.org/users-guide/
http://www.drbd.org/docs/about/
http://linux-ha.org/  [site search nfs]

-- 
Todd Denniston
Crane Division, Naval Surface Warfare Center (NSWC Crane)
Harnessing the Power of Technology for the Warfighter



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