Cyrus & ZFS performance

[Dale Ghent]

On Jul 4, 2007, at 12:59 PM, Vincent Fox wrote:

> Sun recommends against the 3511 in most literature I read, saying  
> that the SATA drives
> are slower and not going to handle as much IOPS loading.  But they  
> are working out okay
> for you?  Perhaps it's just vendor upsell to the more expensive  
> 3510FC....

It's upselling. These 3511s (two units, each unit comprising of a  
3511 with dual controllers and an attached 3511 JBOD, the head and  
JBOS stocked with 250GB and 500GB drives respectively) were recently  
decommissioned from database work and did that job well for 1.5  
years. The reliability warnings given by Sun and others are just one  
way they try to urge you to go with with FC drives... half the  
capacity at twice the cost. Perhaps more performance with FC, yes,  
but not persuasively faster for our purposes at least.

> We are actually doing SAN MultiPath, so hardware paranoia first,  
> and then ZFS on top
> of that for even more.

Similar here, as well. Each of our X4100M2s have a two port Qlogic  
2462 card, with each port connected to a separate switch. Each of our  
3511s are connected to two switches as well, with their LUNs being  
advertised out of all host ports. mpxio does its job well here. Each  
3511 is also in separate data centers in separate buildings, with my  
SAN covering it all... with ZFS mirroring, we essentially have real- 
time replication between two geographically distinct places. If one  
data center were to be lost, everyone's mail spool is still fine in  
another building and ZFS on the Cyrus servers just sees that as one  
side of the mirror going down.

/dale

--
Dale Ghent
Specialist, Storage and UNIX Systems
UMBC - Office of Information Technology
ECS 201 - x51705