I hear this often when people are first getting into iSCSI storage, “What switch should I get?” Here’s what I jotted down from Dell EqualLogic engineers today at the EqualLogic User Conference
iSCSI Best Practices session
NOTES
port buffering ... want inbound and outbound
shared vs dedicated buffer architecture … dedicated obviously better but more $
make sure switches do flow control in BOTH directions in/out
minimize spanning tree
use rapid spanning tree mode on interswitch links
Trunking - also called ISL, LAG, PaGP, LACP
Best Trunking is 1:1 network capacity
Acceptable trunking is 70-80% of network capacity
So if you have 2 arrays w/ 3x1Gb links, you should have 6Gb between switches (1:1)..or at min 6Gbx.7 (70%)=4.2Gb=5Gb between switchesTrunking < Stacking < Chassis Switch
What makes a good switch???
Buffers = 256K per port (guaranteed) [128-256K ok in 3 or less array setups]
flow control ... at min need receive … both directions best
Check for oversubscription in backplane
for non-stacking switches .. best if they have at least 2 10Gb "uplink" ports
continued on part 2
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