DS2405 management

[Enrico Venturi]

Hello colleagues,
I want to use a DS2405 storage system with 15 disk units; I'd like to use the fc entry switch 8B but HP says "It isn't certificated yet!", so, if I want to share the DS2405 units among more nodes I need to directly connect the nods to the DS2405 ports.

My question is:
the DS2405 has 4 ports in the rear panel; are they full available or there is some redundancy mechanism? can I connect 4 nodes to the 4 ports?

Thanks to you all.
Enrico

[Vincent Fleming]

The 4 ports are in/out of 2 (redundant) FC/AL loops.

You can use a P4459A loop switch with the DS2405 in Windows environments (with some restrictions), if that helps.

Switch support is due out soon.

Strictly speaking, you should be able to connect 4 hosts (single connect each) to a DS2405. Do not attempt to access the same drive from 2 hosts at the same time. The redundant loops on the drives are active/passive. I don't think this is a support configuration, however.

Good luck!

[Enrico Venturi]

I want to use this system in place of the SC10, in a High Availability cluster based on MC/Service Guard.
I cannot use the proposed alternative solution.
For sure there is NOT the double access to the same disk drive.
My concern was about the risk coming from the use of both the LCC ports in the same time.
Some of my colleagues reported strange behaviours, i.e. if the storage contains 2 disk drives, each node sees 8 (2 x 4) disks!! each of them on a different hw path.

[Enrico Venturi]

any plan about the fc entry switch 8B qualification by HP?

[Vincent Fleming]

The info I saw today said switch support is scheduled for 4Q02 (end of year). It's hard to tell how accurate these dates are or when they were last updated.

My guess is that it will be available within the next few months.

Now, let me explain the multiple views of the drives...

The FC/AL loops are redundant - which means that all the drives are on both loops. A single system connected to the DS over both FC/AL connections will see at least 2 drives for each physical drive - redundant paths. Use PVLINKs to configure this feature for automatic path failover.
See your LVM docs for more details.

Don't forget that the connections on the DS are in/out so they can be daisey-chained. If/when you hook this to a switch, connect ONLY ONE port of the LCCs to the switch (2 connections total, one from each LCC)

You can use the VA74xx disk array documentation for examples of daisey-chaining the DS2405s.

If you need something today - I can recommend the VA series arrays - they are a bit more expensive than just JBOD (DS2405), but have lots of nifty features and are a lot faster.

Good luck!

[Eugeny Brychkov]

In addition to Vincent's reply: you can have 8 'representations' of 2 disks if there are 4 paths for each disk. This can be achieved, for example, by connecting all four ports (2x2) of DS2405 to one FC hub/switch
Eugeny