so direct connect, no switch ? I would agree with going with two dual-port HBAs, your config would look something like this:

HBA 1 - port 1  - SPA0

HBA 1 -  port 2 - SPB2

HBA 2 - port 1 - SPA2

HBA 2 - port 2 - SPB0

Thank you for answer,

In either way with or without switch could it be same 2 cards with two 8Gb/s ports on each server?

Thanks

if you had a switch in the middle and did not need the extra bandwidth/throughput i would go with two single port cards and zone them like this:

HBA 1 - SPA0

HBA 1 - SPB2

HBA 2 - SPB0

HBA 2 - SPA2

maybe i misunderstood your last question ?

we would need as much performance as we could get from this device, but could we be able to fully utilize 2 cards with 2 ports each with 8Gb/s on every server? We will use 25 SAS disks (15k) on VNX5100.

thanks

you will saturate your disks before you over-run your HBAs.

you mean that 2 cards with 1 port 8Gb/s per each server would be enough?

thanks

if we could have just simplified view:

1 disk for read requests could generate 180 IOPS

let's have 256 kb per I/O

and we have 24 disks

so for read requests in optimistic scenario we have: 180 * 256 * 24 = 1,10592 GB or 8,84736GBit

as 2 HBA's with 1 port 8gbps = 2 * 8 = 16 GBits

So two 1 port HBAs with 8Gbits per port should be enough, is it correct?

with 100% sequential read, large size i/o,  multiple streams ..you could probably get even more bandwidth because SPs would start prefetching. What application is this for ?

it is SQL server,

I know we should measure the data load, but if we concentrate what VNX5100 storage can on one side and what performance we could guarantee on HBA side maybe we could void performance issues in future.

Can 2 ports that is 16 Gbits be fully utilized by this storage and cause some performance bottleneck on heavy load?

thanks

can your application generate that much workload that it will exceed your HBA specs ? A sas drive is capable of 30MB/s so potentially 720MB/s, so if we are talking about strictly bandwidth i don't see any issue with 2 HBAs handling that. But typically with SQL, especially OLTP you are more concerned with iops and not megabytes.