[DRBD-user] DRBD - Slow Performance

Dan Lavu Dan.Lavu at rivermine.com
Tue Feb 16 15:42:48 CET 2010

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

Maros and Bernd,

All software firewalls were already disabled, this is travelling through an IPSEC tunnel with no ACLs. So as of right now they act as if they're on a LAN. Do you think the IPSEC tunnel and or encryption can impact the performance? Thanks in advance. 


Dan Lavu

-----Original Message-----
From: drbd-user-bounces at lists.linbit.com [mailto:drbd-user-bounces at lists.linbit.com] On Behalf Of Maros Timko
Sent: Tuesday, February 16, 2010 8:11 AM
To: drbd-user at lists.linbit.com
Subject: Re: [DRBD-user] DRBD - Slow Performance

> > When copying a large file to the raid, using SFTP I see IO read and
> > write times of 30-35MB/s and I see transfer rates of 20MB/s. Keep in
> > mind I'm syncing between two datacenters, Texas to Illinois.
> >
> > When it's syncing, iostat shows read write times of 2MB/s. I even
> > created a ramdisk for an external metadisk and I saw no improvement.
> >

I was facing similar behaviour on older DRBD versions in case my
firewall rules were not configured correctly on one of the nodes.
Interestingly it still worked, but was "deadly slow". If you use
firewall(s), try to disable them to test.

> > If my raid can easily write at 30MB/s why is the DRBD sync capped at
> > 2MB/s? This is a RAID 5, with two logical volumes.
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