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To: "<freebsd-fs@freebsd.org>" <freebsd-fs@freebsd.org>,
 Dustin Wenz <dustinwenz@ebureau.com>
Subject: Re: Imposing ZFS latency limits
References: <6116A56E-4565-4485-887E-46E3ED231606@ebureau.com>
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Date: Tue, 23 Oct 2012 12:27:10 -0500
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On Tue, 23 Oct 2012 10:40:16 -0500, Dustin Wenz <dustinwenz@ebureau.com>  
wrote:

> What hypervisor are you using? Is it with a passive JBOD?

VMWare ESXi and Xen accessing ZVOLs on FreeBSD shared via iSCSI (istgt).  
Yes, it's with a passive JBOD. The paths from the hypervisors to the HP  
DL380 head units to the JBODs are redundant all the way down to the disks.  
The SSDs for cache/log exist in the head units to not waste precious space  
in the JBOD chassis.

ZFS basically has full control over everything those disks do.