Rsync performance with large exchange database files

bruce at bruce at
Mon Feb 10 10:12:50 MST 2014

------ Original Message ------
From: "Kevin Korb" <kmk at>
To: rsync at
Sent: 2/10/2014 10:57:08 AM
Subject: Re: Rsync performance with large exchange database files

>Hash: SHA1
>3.1.0 will probably help some.
>What are the specs of the FreeBSD system? I have found that ZFS on
>FreeBSD is extremely RAM hungry. In my experience 8GB of RAM is the
>minimum if dedup is disabled and 16BG of RAM for when dedup is enabled.
>Also, a cache disk helps a lot.

The FreeBSD system has 32GB of ram, dual Xeon E5620 cpus, the ZFS pool 
is a 6 disk (HGST 7.2K SATA 2TB drives) raidz2 array.  There's no 
compression or deduplication enabled on the pool.  There isn't any cache 
disks setup though.

I'm starting to do some read-performance tests on the windows machine to 
see if there's a problem there.

When watching the rsync processes I'm not always clear which end it's 
waiting on.

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