This switch is really not recommended for iSCSI and isn’t included in the tested switches for use with EqualLogic Arrays. See the Hardware compatibility matrix (http://en.community.dell.com/dell-groups/dtcmedia/m/mediagallery/20438558)
Typically, it will not deliver the expected performance for your SAN simple due to the fact that the C3850 switch is considered a “wiring closet” switch and not “Storage Network”/“Data Center”/”Fabric” designed switch (largely due to the buffer size for each port are small compared to storage network/data center switches).
So in theory, this switch might handle mostly random, small block IO, as long as this IO profile does not change in the future, but it would not be able to handle your iSCSI SAN traffic if you are doing a lot of large block IO (greater than 8K). You will want to consider a more powerful switch.
The few items to consider;
Your SAN switches should be configured for iSCSI traffic exclusively and dedicated to the SAN network.Avoid using any of the other ports for non-iSCSI traffic unless for administration (i.e., its ok to add a port or two on a separate VLAN for any Management network or monitoring software of the switches, etc., but do not pass LAN or other user traffic across the switch).
Configure a separate VLAN for iSCSI and DO NOT use the default VLAN, the default VLAN is implementation and should be reserved just for administrative traffic (this is true regardless if setting up iSCSI). It is recommended that all traffic be configured on VLANs other than VLAN 1, primarily to prevent unnecessary broadcast and multicast traffic from being processed by the Network Management Processor (NMP) of the supervisor.
Plug your Host iSCSI and Array cable connections staggered across two or more ASIC’s to avoid over subscribing the port and ACIS’s buffers.
Regarding stacking cable, verses ISL’s (trunk group), both work equally well.Stacking is much easier to implement and has some advantages during maintenance on the switches.Also, stacking typically has a dedicated port so you don’t lose 6x ports for the needed bandwidth required for your ISL’s (a simple calculation for EqualLogic ISL total is:you will need to setup at least 2 ISL ports per member dedicated to the trunking between the switches (note that 2 ports is the minimum ISL’s between switch for a single member group), however the ideal setup would have one ISL port per each active array port, so in your case you have 4 members each with 3 active per member, so 4x3= 12 ISL Ports are needed (or 12Gb’s per ISL), and if your SAN grows, you would lose an additional 12 ports to connect the next switch, as you can see ISL port use adds up quickly).Much better to use a stacking cable if possible.
For specific configuration on switches/hosts see:
http://en.community.dell.com/techcenter/storage/w/wiki/3615.rapid-equallogic-configuration-portal-by-sis
Use the configuration Guide for general information and setup guidelines:
http://en.community.dell.com/techcenter/storage/w/wiki/2639.equallogic-configuration-guide
The Storage Technical Solutions Publications and Resources is useful as well:
http://en.community.dell.com/techcenter/storage/w/wiki/2632.storage-infrastructure-and-solutions-team-publications
Regards,
Joe
