[PVE-User] CEPH planning: Expander vs. SAS 9305-16i / SAS 9305-24i

Alexandre DERUMIER aderumier at odiso.com
Fri Sep 30 07:40:24 CEST 2016

>>So, what is better, with or without expander ? :-)

it's also better without expander.

expander works like a switch, so the disks share the sas bandwidth. 
and also, sometime, expander firmware can be buggy, can give timeout,....

without expander, you should have a dedicated sas connection by disk. 

----- Mail original -----
De: "Denny Fuchs" <linuxmail at 4lin.net>
À: "proxmoxve" <pve-user at pve.proxmox.com>
Envoyé: Jeudi 29 Septembre 2016 21:46:30
Objet: [PVE-User] CEPH planning: Expander vs. SAS 9305-16i / SAS 9305-24i


we want to build a CEPH storage out of 6 OSD Nodes with 24 SSD … we consider now to buy the first test hardware and try it out. But where we don’t know, which is better: i asking :-) 

We want to buy 6 x http://www.aicipc.com/ProductDetail.aspx?ref=RSC-2AH 

But don’t know, if it is better to use the expander version from the chassis and a SAS 9305-16i, or the non expander version with a SAS 9305-24i HBA. The motherboard we are testing is a https://www.asus.com/de/Commercial-Servers-Workstations/Z10PRD16/ and a powerful CPU and 128GB ram for each OSD node. The network switched from 10Gb/s ethernet to 56Gb/s Infiniband …. 

I wrote also the complete (except infiniband) plan also in the forum: 


So, what is better, with or without expander ? :-) 

cu denny 
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