zfs-discuss@opensolaris.org
[Top] [All Lists]

Re: [zfs-discuss] Small stalls slowing down rsync from holding network s

Subject: Re: [zfs-discuss] Small stalls slowing down rsync from holding network saturation every 5 seconds
From: Bob Friesenhahn
Date: Tue, 1 Jun 2010 09:57:30 -0500 CDT
On Mon, 31 May 2010, Sandon Van Ness wrote:
With sequential writes I don't see how parity writing would be any
different from when I just created a 20 disk zpool which is doing the
same writes every 5 seconds but the only difference is it isn't maxing
out CPU usage when doing the writes and and I don't see the transfer
stall during the writes like I did on raidz2.

I am not understanding the above paragraph, but hopefully you agree that raidz2 issues many more writes (based on vdev stripe width) to the underlying disks than a simple non-redundant load-shared pool does. Depending on your system, this might not be an issue, but it is possible that there is an I/O threshold beyond which something (probably hardware) causes a performance issue.

Bob
--
Bob Friesenhahn
bfriesen@xxxxxxxxxxxxxxxxxxx, http://www.simplesystems.org/users/bfriesen/
GraphicsMagick Maintainer,    http://www.GraphicsMagick.org/
_______________________________________________
zfs-discuss mailing list
zfs-discuss@xxxxxxxxxxxxxxx
http://mail.opensolaris.org/mailman/listinfo/zfs-discuss

<Prev in Thread] Current Thread [Next in Thread>